1 Kings 2:32
“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.”
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.
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.
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.
Their blood shall therefore return upon the head of Joab, and upon the head of his seed for ever: but upon David, and upon his seed, and upon his house, and upon his throne, shall there be peace for ever from the Lord.
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.
Counter-Arguments
The strongest case that this verse does not belong in this theme.

Cross-References
“His mischief shall return upon his own head, and his violent dealing shall come down upon his own pate.”
“And it shall be, that whosoever shall go out of the doors of thy house into the street, his blood shall be upon his head, and we will be guiltless: and whosoever shall be with thee in the house, his blood shall be on our head, if any hand be upon him.”
“The Lord hath returned upon thee all the blood of the house of Saul, in whose stead thou hast reigned; and the Lord hath delivered the kingdom into the hand of Absalom thy son: and, behold, thou art taken in thy mischief, because thou art a bloody man.”
“And David said unto him, Thy blood be upon thy head; for thy mouth hath testified against thee, saying, I have slain the Lord’s anointed.”
“And when Abner was returned to Hebron, Joab took him aside in the gate to speak with him quietly, and smote him there under the fifth rib, that he died, for the blood of Asahel his brother.”