Adam Clarke on Matthew 22:44

The Lord (יהוה Yeve or Jehovah) said unto my Lord, אדניע Adni or Adonai, my prop, stay, master, support), Sit thou on my right hand - Take the place of the greatest eminence and authority. Till I make thine enemies thy footstool - till I subdue both Jews and Gentiles under thee, and cause them to acknowledge thee as their sovereign and Lord. This quotation is taken from Psa 110:1; and, from it, these two points are clear:

1. That David wrote it by the inspiration of God; and

2. That it is a prophetic declaration of the Messiah.