Although the narrative does not explicitly criticize the quality of Kayin's offering, some commentators look for subtle textual clues that this was indeed the cause of Hashem's displeasure.
"וַיְהִי מִקֵּץ יָמִים" – Philo deduces from these words that Kayin brought his offering only "after some days" and not in a timely fashion.
2 "מִפְּרִי הָאֲדָמָה" – Philo notes that the text mentions that Kayin gave only from the "fruits" and not from the "first fruits" (cf. Hevel who brings "מִבְּכֹרוֹת צֹאנוֹ וּמֵחֶלְבֵהֶן"). Bereshit Rabbah and subsequent Midrashim go even further and say that Kayin brought inferior quality produce or his leftovers as a sacrifice.
"וַיְהִי הֶבֶל רֹעֵה צֹאן וְקַיִן הָיָה עֹבֵד אֲדָמָה" – This approach would understand that the ordering of the sons is insignificant, and Hevel appears first in this verse for purely literary reasons.
3 "וְאֶל קַיִן וְאֶל מִנְחָתוֹ לֹא שָׁעָה" – Hashem rejected Kayin because of his sacrifice.
"אִם תֵּיטִיב שְׂאֵת" – R. Yosef Bekhor Shor explains that Hashem is telling Kayin that he needs to bring a higher quality offering.
4 Attitude regarding sacrifices – This approach views sacrifices as an essential expression of devotion to God.
These commentators assert that Kayin's sacrifice was not accepted due to his generally wicked behavior, rather than because of the quality of the sacrifice itself. According to them, the difference in character between Kayin and Hevel was reflected in their occupational choices. Kayin's choice to be a farmer symbolized his pursuit of material gain, while Hevel's opting to be a shepherd provided him with the time and opportunities for spiritual growth.
"וַיְהִי הֶבֶל רֹעֵה צֹאן וְקַיִן הָיָה עֹבֵד אֲדָמָה" – The precedence given to Hevel (despite his being younger) and his occupation teaches that the shepherding profession was more noble.
Philo also notes that being a shepherd is good preparation for being a king, and both he and
Tanchuma (Buber) provide examples of righteous characters being tested by how they tended to their flocks.
6 On the flip side of the coin,
Lekach Tov points to additional cases of tillers of the land who sinned.
A culture clash – R. Hirsch notes that the contrast between Kayin and Hevel is representative of the divide between the Egyptian agrarian civilization and the Hebrew nomadic shepherding culture. The former's self-reliance leads to an oppressive, enslaving society, while the latter paves the way for belief in and dependence on Hashem. This clash is manifest in the Egyptian attitude of "כִּי תוֹעֲבַת מִצְרַיִם כָּל רֹעֵה צֹאן".
7 Similarly, in Mesopotamian myths
8 which have some points of contact with our story, it is the farmer, rather than the shepherd, who is supreme. Thus, our story may contain an underlying polemic against the neighboring cultures with which the Children of Israel were familiar.
"וַיְהִי מִקֵּץ יָמִים" – This phrase does not signify a delay in the sacrifice, but rather simply the time it took to work the land until its produce was ready to be offered.
9 "מִפְּרִי הָאֲדָמָה" – Abarbanel asserts that even if Kain's offering was not of the best quality, this would not have been sufficient cause for it to be completely rejected, as the Rabbis teach that "אחד המרבה ואחד הממעיט ובלבד שיכוין לבו לשמים".
10 "לַפֶּתַח חַטָּאת רֹבֵץ" – Chaim Gilad
11 proposes that the word "פֶּתַח" here connotes a field, as it does in several other Biblical verses.
12 Y. Rozenson
13 takes this a step further in suggesting that the crouching sin lies in Kayin's agricultural profession.
"וְאֶל קַיִן וְאֶל מִנְחָתוֹ לֹא שָׁעָה" – Philo notes that the verse emphasizes that Hashem rejected Kayin himself, first and foremost, and not just his sacrifice.
Attitude regarding sacrifices – This approach assigns lesser value to material sacrifices, and believes that the primary service of God is in the heart.
This option maintains that while Kayin may have perceived the failure of his crops as Hashem actively rejecting his sacrifice, in reality, this merely reflected that farming is a riskier enterprise than shepherding, as crops are more dependent on rainfall.
"וַיְהִי הֶבֶל רֹעֵה צֹאן וְקַיִן הָיָה עֹבֵד אֲדָמָה" – Hevel's profession is mentioned first because of the greater chances of its success.
"וְאֶל קַיִן וְאֶל מִנְחָתוֹ לֹא שָׁעָה" – Ralbag
14 explains that rain did not come and Kayin's crops did not grow, while Hevel succeeded in his material endeavors. This stands in stark contrast to commentators
15 who suggest that Hashem's disapproval of Kayin's sacrifice was manifest through the absence of a Heavenly fire descending to consume his offering.
Divine providence and the efficacy of sacrifices – According to this approach, the message to Kayin is that Hashem is not a vending machine into which one inserts a sacrifice and out comes the produce.