Abel was a herdsman in Hebrew scripture; the younger son of the first human beings, Adam and Eve. According to Genesis 4:1-9, he was murdered by his older brother Cain, the farmer, because each had made an harvest sacrificial offering to God; Abel's offering was accepted while Cain's was not; therefore Cain became jealous and slough his brother. Abel's offering was accepted by God because his offering of the firstlings of his flock and the fat thereof represented the atonement blood; by his offering Abel recognized his need of atonement for sin, whereas Cain's offering did not. The recognition of this need of atonement for sin was recognized early in Jewish scripture and often, if not constantly repeated. It should be noted, as some suggest, that God never required this act of sacrificial offering; it was devised by the brothers, or man, and the first recorded such offering. Rabbinic exegesis took Cain's offence to be a denial of eternal life and thus of ultimate accountability. Another inference that has been drawn from this scriptural incident is that it symbolizes the conflict between the agricultural and the nomadic way of life, or the farmer and the cattleman. A.G.H.
Bowker, John, The Oxford Dictionary of World Religions, New York, Oxford University Press, 1997, p. 5