Biblical People
Cain. [Heb. Qayin, commonly "worker in metal," or "spear," but according to Gen 4:1, "one acquired." Gr. Kain.]

The eldest son of Adam and Eve, brother and murderer of Abel. A farmer by occupation, he offered as a sacrifice the produce of his fields. When God rejected his offering and accepted that of his brother, Cain became jealous and murdered his brother (Gen 4:1-16). The NT indicates an ethical cause for the rejection of Cain. Abel was righteous (Mt 23:35), while the way of Cain (Jude 11) was evil. John says that Cain was of that wicked one and that he slew his brother because his "works were evil, and his brother's righteous" (1 Jn 3:12). The author of Heb 11:4 implies that lack of faith was the reason for the rejection of Cain's offering. As punishment for his crime, Cain was forced to live the life of an exile. He was given a mark, the exact nature of which is not known, as a protection or sign of protection against blood revenge (Gen 4:15, 16) -- Seventh-day Adventist Bible Dictionary.