A reader may wonder: What was wrong with Cain’s sacrifice?
Professor Robert Alter writes that the biblical narrator used several techniques to convey meaning, e.g., statements by the anonymous narrator, by God, by heroes or heroines, by verbal clues, by juxtaposition of material, by characterization, and by effects of actions. Applying this technique, the verbal clues of the narrative can yield a number of interpretations that reveal the quality of Cain’s sacrifice. Some early rabbinic sources think Cain offered an inferior grade of sacrifice. Unlike his brother who offers the “firstlings of his flock,” Cain does not offer the “firstfruits” of his field. This could suggest that the rabbis may have indeed been correct in their scriptural observation.
This exposition would certainly be consistent with the prophetic message of sacrifices, e.g., the offering in sacrifice of a lame, sick, or blind animal is expressly forbidden in the Torah (Lev. 22:17-25; Deut. 17:1). However, it is in the prophetic literature, this reason for this proscription becomes lucid and understandable.
“So says the LORD of hosts to you, O priests, who despise his name. But you ask, ‘How have we despised your name?’ By offering polluted food on my altar! Then you ask, ‘How have we polluted it?’ By saying the table of the LORD may be slighted! When you offer a blind animal for sacrifice, is this not evil? When you offer the lame or the sick, is it not evil? Present it to your governor; see if he will accept it, or welcome you, says the LORD of hosts” (Malachai 1:6-8).
However, what if Cain’s sacrifice failed because of an entirely different reason–namely, his attitude?
Here too, Philo’s exposition may shed some light. According to him, a bad person’s offering will never be considered a “true sacrifice,” for “even if he were to bring the altar ten thousand oxen every day without intermission; for his most important and indispensable offering, namely his soul, is polluted. And it is impious for polluted things to come near to the altar.” In other words, the worshiper’s attitude is even more important than what the actual sacrifice, which may be physically fine. Philo of Alexandria seems to be suggesting that so long as the heart and soul of the worshiper remains tinged with selfishness and pride, these kinds of moral imperfections will mar the beauty of any offering that is brought to the altar of God.