David heard [about it] later and said: "I and my kingdom are forever innocent before the Lord concerning the blood of Abner son of Ner.
May it hang over Joab's head and his father's whole house, and may the house of Joab never be without someone who has an infection or leprosy or a man who can only work a spindle or someone who falls by the sword or starves."
References for 2 Samuel 3:29
Joab and his brother Abishai killed Abner because he had put their brother Asahel to death in the battle at Gibeon.
References for 2 Samuel 3:30
David then ordered Joab and all the people who were with him, "Tear your clothes, put on sackcloth, and mourn over Abner." And King David walked behind the funeral procession.
References for 2 Samuel 3:31
When they buried Abner in Hebron, the king wept aloud at Abner's tomb. All the people wept,
and the king sang a lament for Abner: Should Abner die as a fool dies?
References for 2 Samuel 3:33
Your hands were not bound, your feet not placed in bronze [shackles]. You fell like one who falls victim to criminals. And all the people wept over him even more.
Then they came to urge David to eat bread while it was still day, but David took an oath: "May God punish me and do so severely if I taste bread or anything else before sunset!"
References for 2 Samuel 3:35
All the people took note of this, and it pleased them. In fact, everything the king did pleased them.
On that day all the troops and all Israel were convinced that the king had no part in the killing of Abner son of Ner.
Then the king said to his soldiers, "You must know that a great leader has fallen in Israel today.
As for me, even though I am the anointed king, I have little power today. These men, the sons of Zeruiah, are too fierce for me. May the Lord repay the evildoer according to his evil!"