'Horns of the Altar' in the Bible

Adonijah feared Solomon, so he got up and went and grabbed hold of the horns of the altar.

Solomon was told, "Look, Adonijah fears you; see, he has taken hold of the horns of the altar, saying, 'May King Solomon solemnly promise me today that he will not kill his servant with the sword.'"

When the news reached Joab (for Joab had supported Adonijah, although he had not supported Absalom), he ran to the tent of the Lord and grabbed hold of the horns of the altar.