Genesis 4:
Abel offered his best with faith and Cain didn't. Cain knew better. He acted unrighteously:Now Abel kept flocks, and Cain worked the soil. 3 In the course of time Cain brought some of the fruits of the soil as an offering to the Lord. 4 And Abel also brought an offering—fat portions from some of the firstborn of his flock. The Lord looked with favor on Abel and his offering, 5 but on Cain and his offering he did not look with favor.
Hebrews 11:8 Now Cain said to his brother Abel, “Let’s go out to the field.” While they were in the field, Cain attacked his brother Abel and killed him.
4a By faith Abel brought God a better offering than Cain did. By faith he was commended as righteous