'Horns of the Altar' in the Bible

Adonijah feared because of Solomon; and he arose, and went, and caught hold on the horns of the altar.

It was told Solomon, saying, "Behold, Adonijah fears king Solomon; for, behold, he has laid hold on the horns of the altar, saying, 'Let king Solomon swear to me first that he will not kill his servant with the sword.'"

The news came to Joab; for Joab had turned after Adonijah, though he did not turn after Absalom. Joab fled to the Tent of the LORD, and caught hold on the horns of the altar.