He said unto them,
How then does David in the Spirit call him Lord, saying,
Read Chapter 22
John Chrysostom
AD 407
For since He was now about to go on to His passion, He sees forth the prophecy that plainly proclaims Him to be Lord; and not as having come to do this without occasion, nor as having made this His aim, but from a reasonable cause.
For having asked them first, since they answered not the truth concerning Him (for they said He was a mere man), to overthrow their mistaken opinion, He thus introduces David proclaiming His Godhead. For they indeed supposed that He was a mere man, wherefore also they said, the Son of David; but He to correct this brings in the prophet witnessing to His being Lord, and the genuineness of His Sonship, and His equality in honor with His Father.