<li>One of the techniques often employed by Midrash is the identification of different Biblical characters one with another, a method which can be termed the "Law of Conservation of Biblical Characters".</li>
+
<li>In many cases, an anonymous or lesser known character (or even objects, places, and dates) is identified with a named and more famous figure. In other instances, two well-known personalities are identified as one and the same person. Sometimes, a person might even be connected to numerous other figures.</li>
+
<li>The method stems from the Midrashic belief in the omnisignificance of Torah, leading it to develop the identities of unknown figures whose presence in the text is otherwise not understandable.</li>
+
<li>The technique is often employed to resolve exegetical or theological questions, to amplify the merits of the righteous and the faults of villainous figures or to mitigate seeming sins of the Patriarchs, and to demonstrate historical continuity.</li>
+
<li>Often, textual links and contextual parallels further motivate and / or bolster the identifications.</li>
+
</ul>
+
<h2>Consolidation of Characters</h2>
<h2>Consolidation of Characters</h2>
−
<p><b>Identification of three or more different names</b></p>
+
<p>Below are many examples of character consolidation with sources and links for further discussion.</p>
−
<ul>
+
<p style="padding-left: 30px;"> <b>I. Identification of three or more different names as the same person:<br/></b></p>
−
<li>Moshe – Vayikra Rabbah</li>
+
<ul style="padding-left: 30px;">
−
<li>Yitro – Mekhilta DeRabbi Yishmael Yitro Amalek 1, see our discussion in Shemot 18.</li>
<li>Sancheriv and other Assyrian kings – Bavli Sanhedrin 94a</li>
+
<li>Nevat and other evil doers – <multilink><a href="BavliSanhedrin101b" data-aht="source">Bavli Sanhedrin 101b</a><a href="BavliSanhedrin101b" data-aht="source">Sanhedrin 101b</a><a href="Talmud Bavli" data-aht="parshan">About the Bavli</a></multilink></li>
−
<li>Koresh and other Persian kings – Seder Olam Rabbah 30, Bavli R"H 3b</li>
+
<li>Sancheriv and other Assyrian kings – <multilink><a href="BavliSanhedrin94a" data-aht="source">Bavli Sanhedrin 94a</a><a href="BavliSanhedrin94a" data-aht="source">Sanhedrin 94a</a><a href="Talmud Bavli" data-aht="parshan">About the Bavli</a></multilink></li>
+
<li>Koresh and other Persian kings – <multilink><a href="SederOlamRabbah30" data-aht="source">Seder Olam Rabbah 30,</a><a href="SederOlamRabbah30" data-aht="source">30</a><a href="Seder Olam Rabbah" data-aht="parshan">About Seder Olam Rabbah</a></multilink> <multilink><a href="BavliRoshHaShanah3b" data-aht="source">Bavli R"H 3b</a><a href="BavliRoshHaShanah3b" data-aht="source">Rosh HaShanah 3b</a><a href="Talmud Bavli" data-aht="parshan">About the Bavli</a></multilink></li>
+
</ul>
+
<p style="padding-left: 30px;"><b>II. Identification of two characters with different names as the same person:</b></p>
+
<ul style="padding-left: 30px;">
+
<li>Yiskah as Sarah – <multilink><a href="SederOlamRabbah20" data-aht="source">Seder Olam Rabbah 21</a><a href="SederOlamRabbah20" data-aht="source">20</a><a href="Seder Olam Rabbah" data-aht="parshan">About Seder Olam Rabbah</a></multilink>, <multilink><a href="BavliSanhedrin69b" data-aht="source">Bavli Sanhedrin 69b</a><a href="BavliSanhedrin69b" data-aht="source">Sanhedrin 69b</a><a href="Talmud Bavli" data-aht="parshan">About the Bavli</a></multilink></li>
<li>Keturah as Hagar – <multilink><a href="BereshitRabbah61-4" data-aht="source">Bereshit Rabbah 61:4</a><a href="BereshitRabbah61-4" data-aht="source">61:4</a><a href="Bereshit Rabbah" data-aht="parshan">About Bereshit Rabbah</a></multilink>. For elaboration, see: <a href="Avraham's Many Wives" data-aht="page">Avraham's Many Wives</a>.</li>
+
<li>Lavan as Bilam – <multilink><a href="TargumYerushalmiYonatanBemidbar22-5" data-aht="source">Targum Yerushalmi (Yonatan)</a><a href="TargumYerushalmiYonatanBemidbar22-5" data-aht="source">Bemidbar 22:5</a><a href="Targum Yerushalmi (Yonatan)" data-aht="parshan">About Targum Yerushalmi (Yonatan)</a></multilink>.<fn>Cf. Bavli Sanhedrin 105a above which equates Lavan with BiIam's father, Beor, instead.</fn> For discussion of the parallels which might lead to the identification, see <a href="Bilam" data-aht="page">Bilam</a>.</li>
+
<li>Shifrah and Puah as Yocheved and Miryam/Elisheva – <multilink><a href="BavliSotah11b" data-aht="source">Bavli Sotah 11b</a><a href="BavliSotah11b" data-aht="source">Sotah 11b</a><a href="Talmud Bavli" data-aht="parshan">About the Bavli</a></multilink>, <multilink><a href="ShemotRabbah1-13" data-aht="source">Shemot Rabbah 1:13</a><a href="ShemotRabbah1-13" data-aht="source">1:13</a><a href="Shemot Rabbah" data-aht="parshan">About Shemot Rabbah</a></multilink>. For discussion, see: <a href="Who are the Midwives" data-aht="page">Who are the Midwives</a>.</li>
<li>Malakhi with Mordechai or Ezra – <multilink><a href="YalkutShimoniMalakhi1-1" data-aht="source">Yalkut Shimoni Malakhi 1:1</a><a href="YalkutShimoniMalakhi1-1" data-aht="source">Malakhi 1:1</a><a href="Yalkut Shimoni" data-aht="parshan">About Yalkut Shimoni</a></multilink></li>
+
<li>Memukhan with Haman – <multilink><a href="BavliMegillah12b" data-aht="source">Bavli Megillah</a><a href="BavliMegillah12b" data-aht="source">Megillah 12b</a><a href="Talmud Bavli" data-aht="parshan">About the Bavli</a></multilink>, <multilink><a href="IbnEzraEstherFirstCommentary3-1" data-aht="source">Ibn Ezra</a><a href="IbnEzraEstherFirstCommentary3-1" data-aht="source">Esther First Commentary 3:1</a><a href="R. Avraham ibn Ezra" data-aht="parshan">About R. Avraham ibn Ezra</a></multilink></li>
+
</ul>
+
<p style="padding-left: 30px;"><b>III. Identification of characters with the same or similar names as the same person:</b></p>
+
<ul style="padding-left: 30px;">
+
<li>Haran the father of Yiska with Haran the brother of Avraham – <multilink><a href="BavliSanhedrin69b" data-aht="source">Bavli Sanhedrin 69b</a><a href="BavliSanhedrin69b" data-aht="source">Sanhedrin 69b</a><a href="Talmud Bavli" data-aht="parshan">About the Bavli</a></multilink></li>
+
<li>Potiphar and Potiphera – <multilink><a href="BavliSotah13b" data-aht="source">Bavli Sotah 13b</a><a href="BavliSotah13b" data-aht="source">Sotah 13b</a><a href="Talmud Bavli" data-aht="parshan">About the Bavli</a></multilink></li>
<li>Calev the son of Chetzron with Calev the son of Yefuneh – <multilink><a href="YerushalmiYevamot10-7" data-aht="source">Yerushalmi Yevamot 10:7</a><a href="YerushalmiYevamot10-7" data-aht="source">Yevamot 10:7</a><a href="Talmud Yerushalmi" data-aht="parshan">About the Yerushalmi</a></multilink>, <multilink><a href="BavliSotah11b" data-aht="source">Bavli Sotah 11b</a><a href="BavliSotah11b" data-aht="source">Sotah 11b</a><a href="Talmud Bavli" data-aht="parshan">About the Bavli</a></multilink> (Cf. <multilink><a href="IbnEzraShemotFirstCommentary24-14" data-aht="source">Ibn Ezra First Commentary Shemot 24:14</a><a href="IbnEzraShemotFirstCommentary24-14" data-aht="source">Shemot First Commentary 24:14</a><a href="R. Avraham ibn Ezra" data-aht="parshan">About R. Avraham ibn Ezra</a></multilink>)</li>
+
<li>Yoel the son of Shemuel with Yoel the prophet –  <multilink><a href="BemidbarRabbah10-5" data-aht="source">Bemidbar Rabbah 10:5</a><a href="BemidbarRabbah10-5" data-aht="source">10:5</a><a href="Bemidbar Rabbah" data-aht="parshan">About Bemidbar Rabbah</a></multilink>, <multilink><a href="MidrashShemuel1" data-aht="source">Midrash Shemuel</a><a href="MidrashShemuel1" data-aht="source">1</a><a href="Midrash Shemuel" data-aht="parshan">About Midrash Shemuel</a></multilink></li>
+
<li>Ovadyah the steward of Ahav with Ovadyah the prophet – <multilink><a href="BavliSanhedrin39b" data-aht="source">Bavli Sanhedrin 39b</a><a href="BavliSanhedrin39b" data-aht="source">Sanhedrin 39b</a><a href="Talmud Bavli" data-aht="parshan">About the Bavli</a></multilink></li>
+
<li>Danel of <a href="Yechezkel14-14-20" data-aht="source">Yechezkel 14:14-20</a> with Daniel of Sefer Daniel</li>
+
</ul>
+
<p style="padding-left: 30px;"><b>IV. Identification of anonymous people with known personalities:</b></p>
<li>Datan and Aviram as the sinners in Egypt and the wilderness – <multilink><a href="ShemotRabbah1-30" data-aht="source">Shemot Rabbah 1:30</a><a href="ShemotRabbah1-30" data-aht="source">1:30</a><a href="Shemot Rabbah" data-aht="parshan">About Shemot Rabbah</a></multilink>, <multilink><a href="TanchumaShemot10" data-aht="source">Tanchuma Shemot 10</a><a href="TanchumaShemot10" data-aht="source">Shemot 10</a><a href="Tanchuma" data-aht="parshan">About the Tanchuma</a></multilink>, <multilink><a href="TanchumaBuberBeshalach24" data-aht="source">Tanchuma Buber Beshalach 24</a><a href="TanchumaBuberBeshalach24" data-aht="source">Beshalach 24</a><a href="Tanchuma" data-aht="parshan">About the Tanchuma</a></multilink></li>
+
<li>Zipporah as the Cushite whom Moshe married – <multilink><a href="SifreBemidbar12-1" data-aht="source">Sifre Bemidbar</a><a href="SifreBemidbar12-1" data-aht="source">12:1</a><a href="Sifre Bemidbar" data-aht="parshan">About Sifre Bemidbar</a></multilink>, <multilink><a href="TanchumaTzav13" data-aht="source">Tanchuma</a><a href="TanchumaTzav13" data-aht="source">Tzav 13</a><a href="Tanchuma" data-aht="parshan">About the Tanchuma</a></multilink>, <multilink><a href="PirkeiDeRabbiEliezer53" data-aht="source">Pirkei DeRabbi Eliezer</a><a href="PirkeiDeRabbiEliezer53" data-aht="source">53</a><a href="Pirkei DeRabbi Eliezer" data-aht="parshan">About Pirkei DeRabbi Eliezer</a></multilink>.  See also: <a href="Miryam's Critique of Moshe and his Cushite Marriage" data-aht="page">Miryam's Critique of Moshe and his Cushite Marriage</a></li>
+
<li>Calev and Pinchas as Yehoshua's spies – <multilink><a href="TanchumaBuberShelach1" data-aht="source">Tanchuma Buber Shelach 1</a><a href="TanchumaBuberShelach1" data-aht="source">Shelach 1</a><a href="Tanchuma" data-aht="parshan">About the Tanchuma</a></multilink></li>
+
<li>Yonah as the boy brought back to life by Eliyahu – <a href="PirkeiDeRabbiEliezer33" data-aht="source">Pirkei DeRabbi Eliezer 33</a>. See <a href="Eliyahu and Yonah" data-aht="page">Eliyahu and Yonah</a> for other connections between the two figures.</li>
<p><b>Identification of two characters with different names as the same person:</b></p>
+
<p style="padding-left: 30px;"><b>V.  Identification of anonymous people one with another:</b></p>
−
<ul>
+
<ul style="padding-left: 30px;">
−
<li>Yiskah as Sarah – Seder Olam Rabbah 21, Bavli Sanhedrin 69b</li>
+
<li>Paroh in Shemot 1-2 with Paroh of Bereshit 37-50 and Paroh of Shemot 3-15 – <multilink><a href="BavliSotah11a" data-aht="source">Bavli Sotah 11a</a><a href="BavliSotah11a" data-aht="source">Sotah 11a</a><a href="Talmud Bavli" data-aht="parshan">About the Bavli</a></multilink>. See discussion in <a href="New King or Dynasty" data-aht="page">New King or Dynasty</a></li>
−
<li>Malkizedek as Shem – Bereshit Rabbah 56:10</li>
+
<li>Paroh of the Exodus with the King of Nineveh of Sefer Yonah – <multilink><a href="PirkeiDeRabbiEliezer53" data-aht="source">Pirkei DeRabbi Eliezer</a><a href="PirkeiDeRabbiEliezer53" data-aht="source">53</a><a href="Pirkei DeRabbi Eliezer" data-aht="parshan">About Pirkei DeRabbi Eliezer</a></multilink>, (see also <a href="Hardened Hearts" data-aht="page">Hardened Hearts</a>), <multilink><a href="YalkutShimoniShemot5-1" data-aht="source">Yalkut Shimoni Shemot 5:1</a><a href="YalkutShimoniShemot5-1" data-aht="source">Shemot 5:1</a><a href="Yalkut Shimoni" data-aht="parshan">About Yalkut Shimoni</a></multilink></li>
−
<li>Keturah as Hagar – Bereshit Rabbah 61:4</li>
+
<li>The officers of the nation in Egypt with the princes or seventy elders – <multilink><a href="ShemotRabbah5-20" data-aht="source">Shemot Rabbah 5:20</a><a href="ShemotRabbah5-20" data-aht="source">5:20</a><a href="Shemot Rabbah" data-aht="parshan">About Shemot Rabbah</a></multilink>, <multilink><a href="BemidbarRabbah12-16" data-aht="source">Bemidbar Rabbah 12:16</a><a href="BemidbarRabbah12-16" data-aht="source">12:16</a><a href="Bemidbar Rabbah" data-aht="parshan">About Bemidbar Rabbah</a></multilink></li>
−
<li>Shifrah and Puah as Yocheved and Miryam/Elisheva – Shemot Rabbah 1:13</li>
−
<li>Efrat as Miryam – Shemot Rabbah 1:17</li>
−
<li>Pinchas as Eliyahu – Targum Yerushalmi (Yonatan) Shemot 6:18</li>
</ul>
</ul>
<h2>Consolidation of Objects</h2>
<h2>Consolidation of Objects</h2>
−
<ul>
+
<p style="padding-left: 30px;"><b>I. Identification of objects with other objects:</b></p>
−
<li>Yiskah as Sarah – Seder Olam Rabbah 21, Bavli Sanhedrin 69b</li>
+
<ul style="padding-left: 30px;">
−
<li>Malkizedek as Shem – Bereshit Rabbah 56:10</li>
+
<li>Esav's clothing and the leather garments of Adam and Chavah – <multilink><a href="BereshitRabbah63-13" data-aht="source">Bereshit Rabbah 63:13</a><a href="BereshitRabbah63-13" data-aht="source">63:13</a><a href="BereshitRabbah85-4" data-aht="source">85:4</a><a href="BereshitRabbah91-8" data-aht="source">91:8</a><a href="Bereshit Rabbah" data-aht="parshan">About Bereshit Rabbah</a></multilink></li>
−
<li>Keturah as Hagar – Bereshit Rabbah 61:4</li>
+
<li>Yaakov and Yehudah's staff with Moshe's staff – Yalkut Shimoni Chukat 763</li>
−
<li>Shifrah and Puah as Yocheved and Miryam/Elisheva – Shemot Rabbah 1:13</li>
+
</ul>
−
<li>Efrat as Miryam – Shemot Rabbah 1:17</li>
+
<p style="padding-left: 30px;"><b>II. Identification of places:<br/></b></p>
−
<li>Pinchas as Eliyahu – Targum Yerushalmi (Yonatan) Shemot 6:18</li>
+
<ul style="padding-left: 30px;">
+
<li>Beit El and Yerushalayim –</li>
+
</ul>
+
<p style="padding-left: 30px;"><b>III. Identification of unknown dates with known ones:</b></p>
+
<ul style="padding-left: 30px;">
+
<li>Angel's visit to Lot – 15 Nisan</li>
+
<li>Giving of the Decalogue – 6 Sivan</li>
+
<li>Moshe's descent with the 1st Tablets – 17 Tammuz</li>
+
<li>Moshe's descent with the 2nd Tablets – 10 Tishrei</li>
+
<li>Night of the return of the spies – 9 Av</li>
</ul>
</ul>
−
<h2></h2>
+
<h2>Analysis</h2>
−
+
<p style="padding-left: 30px;"><b> I. Why does the Midrash identify characters?</b></p>
−
<h2>Identification of two characters with the same or similar names</h2>
+
<ul style="padding-left: 30px;">
+
<li><b>Omnisignificance</b> – As Midrash views every word in Torah as significant, it finds the presence of anonymous or unknown figures who play no other role elsewhere troubling.  By identifying such figures with known characters, it can explain why such details are mentioned – See <multilink><a href="RambanShemot6-23" data-aht="source">Ramban Shemot 6:23</a><a href="RambanShemot6-23" data-aht="source">Shemot 6:23</a><a href="R. Moshe b. Nachman (Ramban, Nachmanides)" data-aht="parshan">About R. Moshe b. Nachman</a></multilink>.</li>
+
<li><b>Textual links</b> – Often, textual links and content parallels<fn>See, for instance, the identification between Eliyahu and Pinechas or Lavan and Bilam.</fn> between stories will motivate a certain identification.  People with similar or identical names<fn>See the list above.</fn> or those who play similar roles in different stories will be connected.  Uncommon words<fn>See, for example, mention of the place Rephaim in connection to both Og and the story of the four and five kings, leading (in part) to the identification of Og as the refugee who spoke to Avraham.</fn> shared by two stories might lead to other associations.</li>
+
<li><b>Solve exegetical problems</b> – At times, an identification serves to solve exegetical difficulties. See, for example, <multilink><a href="ShadalBereshit11-29" data-aht="source">Shadal</a><a href="ShadalBereshit11-29" data-aht="source">Bereshit 11:29</a><a href="ShadalBereshit11-29_2" data-aht="source">Bereshit 11:29</a><a href="R. Shemuel David Luzzatto (Shadal)" data-aht="parshan">About R. Shemuel David Luzzatto</a></multilink>'s discussion of the Midrashic identification of Sarah as Yiskah and the discussion of <a href="Yitro – Names" data-aht="page">Yitro's names</a> in Shemot 18.</li>
+
<li><b>Addressing theological issues</b></li>
<ul>
<ul>
−
<li>Haran the father of Yiska with Haran the brother of Avraham – Bavli Sanhedrin 69b</li>
+
<li><b>Apparent misdeeds of the righteous</b> – Giving a Jewish identity to an idolator or Canaanite can obviate problems of apparent "intermarriages" or other undesirable unions. See, for instance, the identification of Shimon's Canaanite wife with Dina at <a href="Did Yaakov's Sons Marry Canaanites" data-aht="page">Did Yaakov's Sons Marry Canaanites</a> or the identification of the Cushite whom Moshe married with Zipporah at <a href="Miryam's Critique of Moshe and his Cushite Marriage" data-aht="page">Miryam's Critique of Moshe and his Cushite Marriage</a>.</li>
−
<li>Potiphar and Potiphera – Bavli Sotah 13b</li>
+
<li><b>Demonstrate reward and punishment</b> – Nechama Leibowitz<fn>See her Iyyunim BeSefer Bemidbar (Jerusalem, 1992): 94-96.</fn> suggests that in certain instances, such as the identification of the officers whipped in Egypt with the seventy elders, the technique serves to demonstrate Divine providence and how good deeds are rewarded and suffering compensated.<fn>See also the identification of Ovadiah who saved prophets in the time of Izevel with Ovadiah the prophet.</fn></li>
−
<li>Hirah and Hiram – Bereshit Rabbah 85:4</li>
−
<li>Calev the son of Chetzron with Calev the son of Yefuneh – Yerushalmi Yevamot 10:7 (see Ibn Ezra Short Commentary Shemot 24:14)</li>
−
<li>Ovadyah the steward of Ahav with Ovadyah the prophet – Bavli Sanhedrin 39b</li>
</ul>
</ul>
−
+
<li><b>Character development</b> – Identifying villains with other wicked individuals or the worthy with similarly righteous people serves to further blacken or whiten their characters.  This fits the Midrashic tendency to augment the faults of evil characters and amplify the merits of righteous figures. See, for example, the identification of Shifra and Puah with Miryam and Yocheved at <a href="Who are the Midwives" data-aht="page">Who are the Midwives</a>.<fn>See also the conflation of Lavan and Bilam or Datan and Aviram with other rebellious people in the wilderness period.</fn></li>
−
<h2>Identification of anonymous people with known personalities</h2>
+
<li><b>Bridge history</b> – When Midrash connects figures who live centuries apart, its goal might be to bridge history and show continuity over the generations, similar to the concept of מעשה אבות סימן לבנים.</li>
−
<ul>
−
<li>Naamah as Noach's wife – Bereshit Rabbah 23:3</li>
−
<li>Og as the fugitive from Sedom – Bavli Niddah 61a</li>
−
<li>Eliezer and Yishmael as Avraham's servants – Bereshit Rabbah 48:13, Vayikra Rabbah 20:2</li>
−
<li>Dinah as Shimon's wife and Asenat's mother – Bereshit Rabbah 80:11</li>
−
<li>Menashe as Yosef's steward – Bereshit Rabbah 91:8</li>
−
<li>Datan and Aviram as the sinners in Egypt and the wilderness – Shemot Rabbah 1:30, Tanchuma Buber Beshalach 24</li>
−
<li>Calev and Pinchas as Yehoshua's spies – Tanchuma Buber Shelach 1</li>
−
<li>Eved Melekh HaKushi as Barukh – Pirke DeRabbi Eliezer 53</li>
</ul>
</ul>
−
+
<p style="padding-left: 30px;"><b>II. Difficulties with method:</b></p>
−
<h2>Identification of one anonymous person/group with another</h2>
+
<ul style="padding-left: 30px;">
−
<ul>
+
<li>Why would Tanakh use different names in different places?</li>
−
<li>Paroh in Shemot 1-2 with Paroh of Bereshit 37-50 and Paroh of Shemot 3-15 – see Melekh Chadash</li>
−
<li>The officers of the nation in Egypt with the princes or seventy elders – Bemidbar Rabbah 12:16, Shemot Rabbah 5:20</li>
One of the techniques often employed by Midrash is the identification of different Biblical characters one with another, a method which can be termed the "Law of Conservation of Biblical Characters".
In many cases, an anonymous or lesser known character (or even objects, places, and dates) is identified with a named and more famous figure. In other instances, two well-known personalities are identified as one and the same person. Sometimes, a person might even be connected to numerous other figures.
The method stems from the Midrashic belief in the omnisignificance of Torah, leading it to develop the identities of unknown figures whose presence in the text is otherwise not understandable.
The technique is often employed to resolve exegetical or theological questions, to amplify the merits of the righteous and the faults of villainous figures or to mitigate seeming sins of the Patriarchs, and to demonstrate historical continuity.
Often, textual links and contextual parallels further motivate and / or bolster the identifications.
Consolidation of Characters
Below are many examples of character consolidation with sources and links for further discussion.
I. Identification of three or more different names as the same person:
Yaakov and Yehudah's staff with Moshe's staff – Yalkut Shimoni Chukat 763
II. Identification of places:
Beit El and Yerushalayim –
III. Identification of unknown dates with known ones:
Angel's visit to Lot – 15 Nisan
Giving of the Decalogue – 6 Sivan
Moshe's descent with the 1st Tablets – 17 Tammuz
Moshe's descent with the 2nd Tablets – 10 Tishrei
Night of the return of the spies – 9 Av
Analysis
I. Why does the Midrash identify characters?
Omnisignificance – As Midrash views every word in Torah as significant, it finds the presence of anonymous or unknown figures who play no other role elsewhere troubling. By identifying such figures with known characters, it can explain why such details are mentioned – See Ramban Shemot 6:23Shemot 6:23About R. Moshe b. Nachman.
Textual links – Often, textual links and content parallels2 between stories will motivate a certain identification. People with similar or identical names3 or those who play similar roles in different stories will be connected. Uncommon words4 shared by two stories might lead to other associations.
Apparent misdeeds of the righteous – Giving a Jewish identity to an idolator or Canaanite can obviate problems of apparent "intermarriages" or other undesirable unions. See, for instance, the identification of Shimon's Canaanite wife with Dina at Did Yaakov's Sons Marry Canaanites or the identification of the Cushite whom Moshe married with Zipporah at Miryam's Critique of Moshe and his Cushite Marriage.
Demonstrate reward and punishment – Nechama Leibowitz5 suggests that in certain instances, such as the identification of the officers whipped in Egypt with the seventy elders, the technique serves to demonstrate Divine providence and how good deeds are rewarded and suffering compensated.6
Character development – Identifying villains with other wicked individuals or the worthy with similarly righteous people serves to further blacken or whiten their characters. This fits the Midrashic tendency to augment the faults of evil characters and amplify the merits of righteous figures. See, for example, the identification of Shifra and Puah with Miryam and Yocheved at Who are the Midwives.7
Bridge history – When Midrash connects figures who live centuries apart, its goal might be to bridge history and show continuity over the generations, similar to the concept of מעשה אבות סימן לבנים.
II. Difficulties with method:
Why would Tanakh use different names in different places?