(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. (29) And it was told king Solomon that Joab was fled unto the tabernacle of the LORD; and, behold, he is by the altar. Then Solomon sent Benaiah the son of Jehoiada, saying, Go, fall upon him. (30) And Benaiah came to the tabernacle of the LORD, and said unto him, Thus saith the king, Come forth. And he said, Nay; but I will die here. And Benaiah brought the king word again, saying, Thus said Joab, and thus he answered me. (31) And the king said unto him, Do as he hath said, and fall upon him, and bury him; that thou mayest take away the innocent blood, which Joab shed, from me, and from the house of my father. (32) And the LORD shall return his blood upon his own head, who fell upon two men more righteous and better than he, and slew them with the sword, my father David not knowing thereof, to wit, Abner the son of Ner, captain of the host of Israel, and Amasa the son of Jether, captain of the host of Judah. (33) Their blood shall therefore return upon the head of Joab, and upon the head of his seed forever: but upon David, and upon his seed, and upon his house, and upon his throne, shall there be peace forever from the LORD. (34) So Benaiah the son of Jehoiada went up, and fell upon him, and slew him: and he was buried in his own house in the wilderness.
The death of Joab is not for his joining in Adonijah's rebellion, but, it is for the murders he had committed. And Solomon evidently, in this instance, meant to take away the blood of iniquity from the kingdom. It was in conformity to the divine law; and Solomon is not the law-maker, but the law-fulfiller. See Genesis 9:5-6. Oh! how sweet is it to the relief of every poor, distressed, burthened conscience, that Jesus hath both fulfilled the law, and paid the penalty to the law, by the sacrifice of himself.