Abel

Cain and Abel (Hebrew: הֶבֶל ,קַיִן‎ Qayin, Heḇel; Arabic: قابيل، هابيل‎‎ Qābīl, Hābīl) were sons of Adam and Eve. Cain, the firstborn, tilled the soil, and his brother Abel was a shepherd. The brothers made sacrifices to God, each of his own produce, but God favored Abel's sacrifice instead of that of Cain. Cain murdered Abel. God punished Cain to a life of wandering, but set a mark on him so that no man would kill him. Cain then wandered in the land of Nod ("Land of Wandering"), where he built a city and fathered the line of Cain. The motive for Cain's crime is typically assumed to be jealousy, but the narrative never states this, nor does it provide a reason for God's rejection of his sacrifice, nor does it explain where he found a wife (later commentators decided she must have been his sister, although Genesis does not explicitly specify his wife's identity).

The story of Cain's murder of Abel and its consequences is told in Genesis 4:1-18: (Translation and notes from Robert Alter, "The Five Books of Moses")

And the human knew Eve his woman and she conceived and bore Cain, and she said, "I have got me a man with the Lord." And she bore as well his brother Abel, and Abel became a herder of sheep while Cain was a tiller of the soil. And it happened in the course of time that Cain brought from the fruit of the soil an offering to the Lord. And Abel too had brought from the choice firstlings of his flock, and the Lord regarded Abel and his offering but did not regard Cain and his offering. And Cain was very incensed, and his face fell. And the Lord said to Cain, "Why are you incensed, and why is your face fallen? For whether you offer well, or whether you do not, at the tent flap sin crouches and for you is its longing, but you will rule over it." And Cain said to Abel his brother, "Let us go out to the field," and when they were in the field Cain rose against Abel his brother and killed him. And the Lord said to Cain, "Where is Abel your brother? And he said, "I do not know: am I my brother's keeper?"

The story continues with God's punishment of Cain: the soil which received his brother's blood will reject him, and he will be a wanderer on the earth. Cain objects that this is too harsh - "whoever finds me will kill me" - and so God adds a sanction against those who would seek to kill Cain:

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