In the Book of Genesis, Abel (Hebrew Hével / Hável) was the second son of Adam. He was slain by Cain, his elder brother as recorded in Genesis 4:1-16. The narrative in Genesis states that "the Lord had respect unto Abel and to his offering, but unto Cain and to his offering he had not respect."
One proposed Hebrew etymology for the word "Abel" is: "AB", meaning "source" in Hebrew, and "EL" meaning "God". Thus Abel is often taken to mean "source of God" (breath), or "transitoriness" (oneness with God). It more probably means herdsman (compare the name "Jabal", Arabic ibil "camels"), and a distinction is drawn between the pastoral Abel and the agriculturist Cain. If Cain is the eponym of the Kenites it is quite possible that Abel was originally a South Judaean demigod or hero; on this, see Winckler, Gesch. Israels, ii. p. 189; E. Meyer, Israeliten, p. 395. A sect of Abelitae, who seem to have lived in North Africa, is mentioned by Augustine (De Haeresibus, lxxxvi.).
The New Testament says that "by faith Abel offered unto God a more excellent sacrifice than Cain" (Epistle to the Hebrews|Hebrews 11:4), and that Cain slew Abel "because his own works were evil and his brother's righteous" (1 John 3:12).
There are several references to Abel in the New Testament.
Jesus speaks of him as "righteous" (Matthew 23:35). "The blood of sprinkling" is said to speak "better things than that of Abel" (Hebrews 12:24); that is, the blood of Jesus is the reality of which the blood of the offering made by Abel was only the type. The comparison is often seen as that between the sacrifice offered by Christ and that offered by Abel, but some believe it compares the blood of Christ calling for mercy and the blood of the murdered Abel calling for vengeance. It is also said (Hebrews 11:4) that "Abel offered unto God a more excellent sacrifice than Cain." This sacrifice was made "by faith;" this faith rested in God, not only as the Creator and the God of providence, but especially in God as the great Redeemer, whose sacrifice was typified by the sacrifices which, no doubt by the divine institution, were offered from the days of Adam downward. On account of that "faith" which looked forward to the great atoning sacrifice, Abel's offering was accepted of God. Cain's offering had no such reference, and therefore was rejected. Abel has been viewed as the first human to die.