“Then, surrounded by the Pharisees, Jesus asked them a question: “What do you think about the Messiah? Whose son is he?” They replied, “He is the son of David.””
“Jesus responded, “Then why does David, speaking under the inspiration of the Spirit, call the Messiah ‘my Lord’? For David said, ‘The Lord said to my Lord, Sit in the place of honor at my right hand until I humble your enemies beneath your feet.’ Since David called the Messiah ‘my Lord,’ how can the Messiah be his son?””
Matthew 22:41-45 NLT
In this passage Jesus is asking the Pharisees a question which seems simple but takes a turn after they answer. They answer by going by scripture which says that the messiah is the son of David
Now in the beginning of Matthew if you read it all it does say Jesus is a descendent of David. This is why Jesus did not say they were wrong. Now the Pharisees said that the messiah is David’s son but Jesus questions that because how can he be the son of David when David calls him his lord ? After Jesus quoted David’s song in psalms the Pharisees didn’t ask him anymore questions because at this point they realized that their answer had made no sense.
Now In acts 2 verses 34-36 it says
For David himself never ascended into heaven, yet he said, ‘The Lord said to my Lord, “Sit in the place of honor at my right hand until I humble your enemies, making them a footstool under your feet.”’ “So let everyone in Israel know for certain that God has made this Jesus, whom you crucified, to be both Lord and Messiah!””
now in psalms 110 verse 1 when David says “The Lord said to my Lord”
He is meaning that the Lord the father which is God is talking to the Lord the son who is our messiah Jesus . David was before Jesus and yet this is what he said so this is why when Jesus asked them “Since David called the Messiah ‘my Lord,’ how can the Messiah be his son?””
Now Jesus’ question was how does David call his own descendent Lord? This had to mean that he knew Jesus which was his descendent would be more worthy and honorable than he is . He also knew that jesus would be the messiah. Another thing is that this passage and also psalms 110 verse 1 proves that the trinity is the right way to believe because it says the Lord said to my Lord . Meaning that the father said to the son . The father the Lord said to My Lord the son. Meaning there is 2 in this passage other wise if we was wrong and there wasn’t 3 (the father, the Son, and the Holy spirit ) then there wouldn’t be a conversation , there wouldn’t be this one said to this one . It would be more like The lord said not the Lord said to my Lord.