C. F. Keil and Franz Delitzsch on 1 Kings 20:39-40

1Ki 20:39-40

When the king passed by, he cried out to him and related the following fictitious tale: He had gone to the war, and a man had come aside to him (סוּר as in Exo 3:3; Jdg 14:8, etc.), and had given a man (a prisoner) into his care with this command, that he was to watch him, and if he should be missing he was to answer for his life with his own life, or to pay a talent of silver (as a punishment). The rest may be easily imagined, namely the request to be saved from this punishment. Ahab answered (1Ki 20:40), משׁפּטך כּן, “thus thy sentence, thou hast decided,” i.e., thou hast pronounced thine own sentence, and must endure the punishment stated.