1 Kings 20:39

And he said to him, “Thus says Yahweh, ‘Because you have let go out of your hand the man whom I had devoted to destruction, therefore your life shall go for his life, and your people for his people.’”

Then they came in to offer sacrifices and burnt offerings. Now Jehu had placed for himself eighty men outside, and he had said, “The one who permits any of the men whom I cause to come into your hands to escape, shall give up his life in exchange.”

“Cursed be the one who does the work of Yahweh with a slack hand, And cursed be the one who restrains his sword from blood.