'Horns of the Altar' in the Bible

And Adonijah will, be afraid of the face of Solomon, and he will rise and go, and lay hold upon the horns of the altar.

And it will be announced to Solomon, saving, Behold, Adonijah was afraid of king Solomon, and behold, he seized upon the horns of the altar, saying, Will king Solomon swear to me according to the day if he will kill his servant with the sword?

And the report came even to Joab: (for Joab turned after Adonijah, and after Absalom he turned not;) and Joab will flee to the tent of Jehovah and will lay hold upon the horns of the altar.