David himself had experienced this once (2 Samuel 23:1–14). When he was king, there was a famine that lasted three years. David asked the Lord what was going on and found out that there was still a bloodguilt from the time of his predecessor Saul. He had killed people of a nation who had been promised—even through the making of a covenant—that nothing would happen to them.
31 The king replied to him, “Do as he has said, strike him down and bury him, and thus take away from me and from my father’s house the guilt for the blood that Joab shed without cause.