Albert Barnes Commentary Matthew 22:45

"If David then calleth him Lord, how is he his son?" — Matthew 22:45 (ASV)

If David, etc. If he was, then, David's Lord; if he was his superior; if he had an existence at that time, how could he be descended from him? They could not answer him. Nor is there any way of answering the question but by the admission that the Messiah was Divine as well as human; that he had an existence at the time of David, and was his Lord and Master, his God and King, and that as man he was descended from him.