“For David ascended not into the heavens: but he says himself, The Lord said to my Lord, Sit you on my right hand, until I make your enemies the footstool of your feet.”
He then again contrasts David's situation with that of Jesus. He had drawn attention to the fact that David was still in his tomb. Now he stresses that, unlike Jesus, David had not ascended into heaven. Here then is One greater than David, great David's greater son, of whom David had said, “The Lord said to my Lord, Sit you on my right hand, until I make your enemies the footstool of your feet.” David had thus prophesied that his superior ‘son', Who was really his Lord, would rise to heaven and take His place at God's right hand, there to await the submission of those who opposed Him.
While as far as we know this Psalm had never specifically been interpreted Messianically (although in general any Davidic psalm was Messianic simply because it spoke of the house of David and was downdated king by king and must therefore finally include reference to the coming son of David) Jesus Himself had certainly taken it as such (Luke 20:41-44; Mark 12:35-37; Matthew 22:41-45 compare Hebrews 1:13). He had further used it in order to demonstrate the superiority of the expected Messiah to David himself.