Mt 22:43-45, Mk 12:35-37, Lk 20:41-44, Acts 2:34-36
In the Old Testament David saw God telling Christ to sit at the right hand of God. (Psalms 110:1)
Psalms 110:1 The Lord said unto my Lord, Sit thou at my right hand, until I make thine enemies thy footstool.
Jesus said that David called the Christ, the son of David, Lord. (Matthew 22:43-45, Mark 12:35-37, Luke 20:41-44)
Matthew 22:43 He saith unto them, How then doth David in spirit call him Lord, saying, 44 The Lord said unto my Lord, Sit thou on my right hand, till I make thine enemies thy footstool? 45 If David then call him Lord, how is he his son?
Mark 12:35 And Jesus answered and said, while he taught in the temple, How say the scribes that Christ is the son of David? 36 For David himself said by the Holy Ghost, The Lord said to my Lord, Sit thou on my right hand, till I make thine enemies thy footstool. 37 David therefore himself calleth him Lord; and whence is he then his son? And the common people heard him gladly.
Luke 20:41 And he said unto them, How say they that Christ is David's son? 42 And David himself saith in the book of Psalms, The Lord said unto my Lord, Sit thou on my right hand, 43 Till I make thine enemies thy footstool. 44 David therefore calleth him Lord, how is he then his son?
Jesus is the Christ whom David called Lord. (Acts 2:34-36)
Acts 2:34 For David is not ascended into the heavens: but he saith himself, The Lord said unto my Lord, Sit thou on my right hand, 35 Until I make thy foes thy footstool. 36 Therefore let all the house of Israel know assuredly, that God hath made the same Jesus, whom ye have crucified, both Lord and Christ.