And he (Aaron) shall take the two goats, and present them before the Lord. And Aaron shall cast lots upon the two goats ; one lot for the Lord, and the other lot for the scapegoat. And Aaron shall bring the goat upon which the Lord’s lot fell, and offer him for a sin offering. But the goat, on which the lot fell to be the scapegoat, shall be presented alive before the Lord, to make an atonement with him, and to let him go for a scapegoat into the wilderness. And Aaron shall lay both his hands upon the head of the live goat, and confess over him all the iniquities of the children of Israel, and all their transgressions in all their sins, putting them upon the head of the goat, and shall send him away by the hand of a fit man into the wilderness.
The quotation is from the sixteenth chapter of Leviticus, in the King James Version of the Bible.
Thus, scapegoat entered the language and has become applied to one chosen arbitrarily or at random to receive the punishment merited by a group.