Adam Clarke on Matthew 22:45

How is he his son? - As the Jews did not attempt to deny the conclusion of our Lord's question, which was, the Messiah is not only the son of David according to the flesh, but he is the Lord of David according to his Divine nature, then it is evident they could not. Indeed, there was no other way of invalidating the argument, but by denying that the prophecy in question related to Christ: but it seems the prophecy was so fully and so generally understood to belong to the Messiah that they did not attempt to do this; for it is immediately added, No man was able to answer him a word - they were completely nonplussed and confounded.