Kings III 21:42

42 And he said to him, Thus saith the Lord, Because thou hast suffered to escape out of thine hand a man appointed to destruction, therefore thy life shall go for his life, and thy people for his people.

Kings III 21:42 In-Context

40 And it came to pass, that thy servant looked round this way and that way, and the man was gone. And the king of Israel said to him, Behold, thou hast also destroyed snares for me.
41 And he hasted, and took away the bandage from his eyes; and the king of Israel recognized him, that he was one of the prophets.
42 And he said to him, Thus saith the Lord, Because thou hast suffered to escape out of thine hand a man appointed to destruction, therefore thy life shall go for his life, and thy people for his people.
43 And the king of Israel departed confounded and discouraged, and came to Samaria.

The Brenton translation of the Septuagint is in the public domain.