Jesus pointed out that the Pharisees" answer contained a problem. How could Messiah be David"s son if David called Him his Lord? Jesus referred to Psalm 110 , the most frequently quoted Old Testament chapter in the New Testament. This was a psalm that David wrote, as is clear from the superscription. Jesus regarded it as He regarded all the Old Testament, namely, inspired by the Holy Spirit ( Matthew 22:43; cf. Acts 4:25; Hebrews 3:7; Hebrews 9:8; Hebrews 10:15; 1 Peter 1:21). Jesus assumed that Psalm 110 was Davidic and Messianic, and the Pharisees agreed. He referred to the psalm"s inspiration here to reinforce its correctness in the minds of His hearers. David had not made a mistake when he wrote this. The "right hand" is the position of highest honor and authority (cf. Matthew 19:28). [source][source][source]
There is good evidence that almost all Jews in Jesus" day regarded Psalm 110 as messianic. [1] Jesus" point was that Messiah was not just David"s descendant, but He was God"s Son also. This is a point that Matthew stressed throughout his Gospel (chs1-2; Matthew 3:17; Matthew 8:20; Matthew 17:5; et al.). Jesus was bringing together the concepts that Messiah was the human son of David and the divine Son of God. [2][source]
Moreover this quotation also shows the preexistence of Messiah. David"s Lord was alive when David lived. Furthermore it reveals plurality within the Godhead. One divine person spoke to another. [source][source][source]
The psalm pictured Messiah at God"s right hand while His enemies were hostile to Him. However, Messiah would crush that hostility eventually. This is precisely the eschatological picture that has been unfolding throughout this Gospel. Rejected by His own, Jesus would return to the Father, but He would return later to earth to establish His kingdom. The Jewish rabbis after Jesus" time interpreted David"s lord as Abraham, not Messiah. [3][source]