2 Samuel 16:9 (KJV)

And thus said Shimei when he cursed, Come out, come out, thou bloody man, and thou man of Belial:

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.

Then said Abishai the son of Zeruiah unto the king, Why should this dead dog curse my lord the king? let me go over, I pray thee, and take off his head.

And the king said, What have I to do with you, ye sons of Zeruiah? so let him curse, because the Lord hath said unto him, Curse David. Who shall then say, Wherefore hast thou done so?

And David said to Abishai, and to all his servants, Behold, my son, which came forth of my bowels, seeketh my life: how much more now may this Benjamite do it? let him alone, and let him curse; for the Lord hath bidden him.