The psalmist wrote that he heard a conversation between Yahweh and David"s Master. Clearly this distinguishes two members of the Godhead. LORD (Yahweh) refers to God the Father and Lord (adonay) refers to God the Song of Solomon , the Messiah or Anointed of God. Yahweh commanded Messiah to sit at His right hand, the traditional place of power and authority. He was to do so until Yahweh has subjugated Messiah"s enemies (cf. Joshua 5:14). Then Yahweh would permit Messiah to rule over them (cf. Psalm 2:8-9; 1 Corinthians 15:25). [source][source][source]
"Originally the victorious king placed his feet on the necks of his vanquished foe (cf. Joshua 10:24; 1 Kings 5:3; Isaiah 51:23). From this practice arose the idiom to make one"s enemy one"s footstool." [1][source]
Jesus Christ quoted Psalm 110:1 to prove that He was not only David"s descendant but the Messiah of whom David wrote ( Mark 12:35-37; cf. Matthew 22:44-45; Luke 20:42-44). Peter and the writer of the epistle to the Hebrews also quoted it to prove the deity of Jesus ( Acts 2:34-36; Acts 5:30-31; Hebrews 1:13; Hebrews 10:11-13). [source][source][source]
"So this single verse displays the divine Person of Christ, His power and the prospect before Him. Together with Psalm 110:4 it underlies most of the New Testament teaching on His glory as Priest-King." [2][source]