Structure of Tefillah

Though we tend to think that the different prayers said each day comprise many individual components, in reality they are essentially composed of just one or both of two main units: Shema and its blessings, and the Amidah and its preparatory and concluding prayers. These two units are independent of each other, and even fulfill distinct obligations:

• Shema and its Blessings
• קבלת עול מלכות שמים – Shema is incorporated into Shacharit and Arvit as a fulfillment of the obligation to accept the yoke of Heaven daily.  As such, it is distinct from the general mitzvah of prayer. It is inserted only in the morning and evening prayers (and not in Minchah) since Devarim mandates that it be said "בְשׇׁכְבְּךָ וּבְקוּמֶךָ", upon sleeping and waking.
• ברכות קריאת שמע – The Shema is prefaced and followed by blessings, giving this unit of prayer an envelope structure.
• Amidah and its Preparatory / Concluding Prayers
  
• "תפילות כנגד תמידין" – The Amidah prayer is related to the obligation of "וַעֲבַדְתֶּם אֵת י"י אֱלֹהֵיכֶם" (Shemot 23:25),¹ and was instituted to replace the Daily Burnt Offering of the morning and afternoon.² As such, the obligatory Amidah prayers are in Shacharit and Minchah, while the Amidah of Arvit is voluntary.
• "שוהים שעה אחת" – R. Yehoshua b. Levi in Bavli BerakhotBerakhot 32bAbout Bavli Berakhot speaks of the need for contemplation³ both before and after saying the Amidah, rather than simply jumping into the prayer and departing immediately afterwards.⁴ The Amidah is, thus, preceded by Tehillim 145, "תהילה לדוד,"‎⁵ (and, in Shacharit, the rest of Pesukei DeZimra), and followed by the Tachanun prayer.  The Amidah framework, then, also has an envelope structure with prayers sandwiching it on both ends.

• Minchah, Selichot, Musaf and Neila – The Amidah Framework
  
• Tefillat Minchah is composed solely of the "Amidah framework". It opens with the psalm, "תהילה לדוד" ("Ashrei"), continues with the Amidah, and concludes with Tachanun.⁶  Selichot follows the same format, with the Selichot and thirteen attributes of Hashem (י"ג מידות) themselves standing in for the Amidah.⁷  The Musaf and Neila prayers are built similarly, also opening with "Ashrei", followed by the Amidah, and only not ending with Tachanun since the nature of the days in which these prayers are said preclude it.

• Arvit –The Shema Framework
• Tefillat Arvit is the inverse of Minchah, essentially comprised of only the "Shema framework". Though at first glance, the presence of the Amidah would suggest otherwise, this is somewhat of a red herring, for the Amidah is not really an integral part of Arvit but rather a secondary, voluntary addition.⁸ As such, it is not surrounded by "Ashrei" and "Tachanun".⁹ This, then, leaves the essence of Arvit as comprising only Shema and its surrounding blessings.
• Shacharit – Combining the Shema and Amidah Frameworks
• Tefillat Shacharit contains both the Shema and Amidah frameworks.  However, rather than being distinct and following one another, they get intertwined.  The desire to juxtapose the blessing of "גאל ישראל"‎ (which follows Shema) with the Amidah prayer¹⁰ led Shema and its blessings to be inserted into the middle of the "Tefilla framework," separating "Ashrei" (and the rest of Pesukei DeZimra) from the Amidah.
• Shacharit = Arvit + Minchah = Shema + Amidah
  
• In summary, then, Shacharit is essentially a combination of the Amidah framework of Minchah and the Shema framework of Arvit. [For a visual, see the Venn diagram on the right.]

The two units discussed above form the central axis of Tefillah.  Around these, certain elements were added:

• Opening of Tefillah – Tefillah opens with a series of blessings and learning:
• ברכות השחר – The morning blessings were not originally part of the synagogue service, but said individually upon waking and dressing.
• ברכות התורה וסדר לימוד – The blessings for learning Torah are followed by a learning session, including passages from Torah, Mishnah and Talmud.
• קרבנות – As prayer is meant to replace the sacrificial service, a collection of sources relating to the various sacrifices is read at the beginning of Shacharit and Minchah (when the Daily Offering was brought).  This section is more extensive in the morning where it forms part of the learning session.
• Expanded Pesukei DeZimra – In the morning, the preparatory period before the Amidah prayer was expanded to include not just Psalm 150, but all of Pesukei DeZimra (including several more Psalms and the Song of the Sea).
• Conclusion to Tefillah
• קדושה דסדרא / סדר לימוד – "Kedusha DeSidra" originated as part of a learning session which took place after the prayer service.
• Saying Goodbye – "עלינו" is said at the end of each of the Tefillot before departing from the synagogue..
• Dividers – Each of these sections of the prayer service is separated by the saying of "Kaddish".