Eve bears a first child, a son, and assumes/hopes she has begotten a man, “the Lord,” according to God’s promise. And why wouldn’t she hope so and how could she know that it would be hundreds of generations of the women’s seed before the Holy Spirit would work the conception of the Son of God in Mary?
Eve calls her second son “breath,” the same word from Ecclesiastes, “Breath of breath, everything is breath” as in “here in this moment and gone in the next.” If Cain is the promised savior, then the next born son is insignificant by comparison.
“The apple doesn’t fall far from the tree,” and so Cain assumes the honorable vocation of tending the ground. But consistent with Adam’s corruption, Cain pretends an offering to God, offering what he would not care about giving away. Abel, by contrast, cares for living animals and offers the very best of them as witness to and thanks for how God provided for him. God articulates the truth which provokes Cain to jealousy, hatred, and murder, which will be evident in all human history but most of all in the experience of Jesus at the hands of the religious authorities in Israel.