Abel, in the Old Testament Book of Genesis, the second son of Adam and Eve and the brother of Cain. Abel was a shepherd, and his older brother, Cain, cultivated the land. Both brothers made an offering to God: Cain gave a portion from his harvest, while Abel offered the firstborn of his flock. When Cain's offering was rejected, he became jealous and killed his brother, Abel (see Genesis 4:2-16). This famous story about fratricide is thought by many theologians to illustrate early nomadic tribal beliefs that filtered down through time into religious thought. Animal herding, the principal occupation of many nomads, was considered more pleasing to their gods than agriculture; hence, Abel's sacrifice was accepted, but Cain's was not (see Hebrews 11:4, 12:24).