In a similar incident Solomon had spared the life of his brother Adonijah.
1 Kings 1:50-53 (NKJV)
50 Now Adonijah was afraid of Solomon; so he arose, and went and took hold of the horns of the altar. 51 And it was told Solomon, saying, “Indeed Adonijah is afraid of King Solomon; for look, he has taken hold of the horns of the altar, saying, ‘Let King Solomon swear to me today that he will not put his servant to death with the sword.’ ” 52 Then Solomon said, “If he proves himself a worthy man, not one hair of him shall fall to the earth; but if wickedness is found in him, he shall die.” 53 So King Solomon sent them to bring him down from the altar. And he came and fell down before King Solomon; and Solomon said to him, “Go to your house.”
But on the other hand he went on to kill Joab whilst he was holding onto the horns
1 Kings 2:28-31 (NKJV)
28 Then news came to Joab, for Joab had defected to Adonijah, though he had not defected to Absalom. So Joab fled to the tabernacle of the LORD, and took hold of the horns of the altar. 29 And King Solomon was told, “Joab has fled to the tabernacle of the LORD; there he is, by the altar.” Then Solomon sent Benaiah the son of Jehoiada, saying, “Go, strike him down.” 30 So Benaiah went to the tabernacle of the LORD, and said to him, “Thus says the king, ‘Come out!’ ” And he said, “No, but I will die here.” And Benaiah brought back word to the king, saying, “Thus said Joab, and thus he answered me.” 31 Then the king said to him, “Do as he has said, and strike him down and bury him, that you may take away from me and from the house of my father the innocent blood which Joab shed.
What could have been the significance of holding the horns of the altar?
Could there be some biblical,extra biblical or historical citations on the significance of holding the horns?