1 Kings 2:28

Then tidings came to Joab: for Joab had turned after Adonijah, though he turned not after Absalom. And Joab fled unto the tabernacle of the LORD, and caught hold on the horns of the altar.

Then tidings came to Joab. The execution of these sentences respectively on Adonijah and Abiathar prepared Joab for his fate. Death, due to his great crimes (Numbers 35:33), would long ago have been inflicted had not his power and popularity with the army been too formidable for the old king. He now fled to the altar, which, though a recognized asylum, afforded no sanctuary to the rebel and murderer (Exodus 21:14). And, as he refused to leave it, he seems to have cherished some faint hope that a religious scruple would have been felt at the thought of violating the sanctity of the place by bloodshed. Benaiah, not liking to assume any responsibility, referred the matter to Solomon, who determined that the law should take its course (Deuteronomy 19:13).