Levirate marriage is the type of marriage in which a brother of a deceased man is obliged to marry his brother's widow. Levirate marriage has been practiced by societies with a strong clan configuration in which exogamous marriage i.e. marriage external the clan is forbidden. It has been so-called in numerous societies around the world.
In the Deuteronomy 25:5–10, under which the brother of a man who dies without children is permitted and encouraged to marry the widow. Either of the parties may refuse to go through with the marriage, but both must go through a ceremony, requested as halizah, involving a symbolic act of renunciation of a yibbum marriage. Sexual relations with one's brother's wife are otherwise forbidden by Leviticus 18 and Leviticus 20.
Jewish custom has seen a unhurried decline of yibbum in favor of halizah, to the point where in near contemporary Jewish communities, and in Israel by mandate of the Chief Rabbinate, yibbum is prohibited.