John Gill Commentary 1 Kings 20:4

"And the king of Israel answered and said, It is according to thy saying, my lord, O king; I am thine, and all that I have." — 1 Kings 20:4 (ASV)

And the king of Israel answered and said, my lord, O king
So he said to Benhadad's messengers, representing him, as acknowledging his sovereignty over him:

according to your saying, I am yours, and all that I have :
which he understood of holding all that he had of him, by giving him homage, and paying him tribute; not that he was to deliver all his substance, and especially his wives and children, into his hands.