Genesis 4:5

Abel was very discerning in his choice of offerings, whereas Cain showed no such discernment. Abel selected and offered the choicest of his firstborn and of his fat ones, while Cain either offered young grains or certain fruits that are found at the same time …

(61) Why, when he had begun with Cain, he still mentions him here in the second place, when he says: "And God had respect unto Abel and unto his offerings; but unto Cain and unto his sacrifices he paid no attention?" (#Ge 4:5). In the …

Since Abel made his offering with a proper attitude and pure intention, "God took notice," the text saysÐthat is, he accepted, he was satisfied, he approved of them; but it called the offerings gifts, by this means dignifying the attitude of the offerer. "And whereas to Cain and his offerings he paid no heed." Notice the precision of Sacred Scripture: by the phrase "he paid no heed" it shows us the rejection of what was offered, and by calling what was offered from the soil offerings he teaches us something else again. I mean, see how he shows us through the very events and terms that the Lord wants all these things to be done by us so that the kind of intention we have should be made clear through the actions we take, and so that we may be in a position to know that we are subject to a Lord and Creator who brought us from nothing to being. In other words, in naming the sheep gifts and calling the things from the earth offerings, Sacred Scripture teaches us that neither the herding of sheep nor the collection of fruits of the earth is what is looked for by the Lord but simply the disposition of one's attitude. Hence in this case, too, one man proved acceptable with his gift on this score, whereas the other was rejected along with his gift on that account. The verse, "God took notice of Abel and his gifts, whereas to Cain and his offering he paid no heed," let us take in a sense befitting God. I mean, the intention in the words is that he communicated to them the awareness that while he was satisfied with one man's choice, he took umbrage at the other's attitude. Such, however, is the way God does things; let us now see what follows. "This annoyed Cain very much and his face fell." What is the meaning of the words, "This annoyed Cain very much"?

Cain was angry because the offering of his brother had been accepted. Cain became angry on account of the fire that had come down and distinguished between the offerings.

And Cain was very angry, and his countenance fell. How did Cain know that the Lord had looked favorably upon Abel and his offerings, but had turned away his face from himself and his offerings, unless, as some have interpreted, the Lord had set fire …