How did King David know the Messiah, who hadn’t even been born yet?
Psalm 110:1 NASB The LORD says to my Lord: "Sit at My right hand Until I make Your enemies a footstool for Your feet."
Two kings are mentioned: God and David’s Lord. David’s Lord sits at the right hand of God, which signifies a place of privilege, authority, and honor. Here it includes the promise that his enemies would be fully subdued.
It is evident that it can only refer, as the ancient Jews fully acknowledged, to the royal dignity, priesthood, victories, and triumphs of the MESSIAH.
This psalm is messianic, which Jesus himself confirms in Mark 12:35-37.
Mark 12:35-37 "And Jesus began to say, as He taught in the temple, "How is it that the scribes say that the Christ is the son of David?
36 "David himself said in the Holy Spirit, 'THE LORD SAID TO MY LORD, "SIT AT MY RIGHT HAND, UNTIL I PUT YOUR ENEMIES BENEATH YOUR FEET."'
37 "David himself calls Him 'Lord '; so in what sense is He his son?" And the large crowd enjoyed listening to Him.
Matt. 22:41-45 Now while the Pharisees were gathered together, Jesus asked them a question:
42 "What do you think about the Christ, whose son is He?" They said to Him, "The son of David."
43 He said to them, "Then how does David in the Spirit call Him 'Lord,' saying,
44 'THE LORD SAID TO MY LORD, "SIT AT MY RIGHT HAND, UNTIL I PUT YOUR ENEMIES BENEATH YOUR FEET "'?
45 "If David then calls Him 'Lord,' how is He his son?"
Luke 20:41-44 "Then He said to them, "How is it that they say the Christ is David's son?
42 "For David himself says in the book of Psalms, 'THE LORD SAID TO MY LORD, "SIT AT MY RIGHT HAND,
43 UNTIL I MAKE YOUR ENEMIES A FOOTSTOOL FOR YOUR FEET."'
44 "Therefore David calls Him 'Lord,' and how is He his son?" For David himself says in the book of Psalms, 'THE LORD SAID TO MY LORD, "SIT AT MY RIGHT HAND,”
Acts 2:34-35 "For it was not David who ascended into heaven, but he himself says: 'THE LORD SAID TO MY LORD, "SIT AT MY RIGHT HAND, 35 UNTIL I MAKE YOUR ENEMIES A FOOTSTOOL FOR YOUR FEET."
Hebrews 10:12-13 “but He, having offered one sacrifice for sins for all time, SAT DOWN AT THE RIGHT HAND OF GOD,
13 waiting from that time onward UNTIL HIS ENEMIES BE MADE A FOOTSTOOL FOR HIS FEET.”
Psalm 110:1 NASB The LORD says to my Lord: "Sit at My right hand Until I make Your enemies a footstool for Your feet."
Two kings are mentioned: God and David’s Lord. David’s Lord sits at the right hand of God, which signifies a place of privilege, authority, and honor. Here it includes the promise that his enemies would be fully subdued.
It is evident that it can only refer, as the ancient Jews fully acknowledged, to the royal dignity, priesthood, victories, and triumphs of the MESSIAH.
This psalm is messianic, which Jesus himself confirms in Mark 12:35-37.
Mark 12:35-37 "And Jesus began to say, as He taught in the temple, "How is it that the scribes say that the Christ is the son of David?
36 "David himself said in the Holy Spirit, 'THE LORD SAID TO MY LORD, "SIT AT MY RIGHT HAND, UNTIL I PUT YOUR ENEMIES BENEATH YOUR FEET."'
37 "David himself calls Him 'Lord '; so in what sense is He his son?" And the large crowd enjoyed listening to Him.
Matt. 22:41-45 Now while the Pharisees were gathered together, Jesus asked them a question:
42 "What do you think about the Christ, whose son is He?" They said to Him, "The son of David."
43 He said to them, "Then how does David in the Spirit call Him 'Lord,' saying,
44 'THE LORD SAID TO MY LORD, "SIT AT MY RIGHT HAND, UNTIL I PUT YOUR ENEMIES BENEATH YOUR FEET "'?
45 "If David then calls Him 'Lord,' how is He his son?"
Luke 20:41-44 "Then He said to them, "How is it that they say the Christ is David's son?
42 "For David himself says in the book of Psalms, 'THE LORD SAID TO MY LORD, "SIT AT MY RIGHT HAND,
43 UNTIL I MAKE YOUR ENEMIES A FOOTSTOOL FOR YOUR FEET."'
44 "Therefore David calls Him 'Lord,' and how is He his son?" For David himself says in the book of Psalms, 'THE LORD SAID TO MY LORD, "SIT AT MY RIGHT HAND,”
Acts 2:34-35 "For it was not David who ascended into heaven, but he himself says: 'THE LORD SAID TO MY LORD, "SIT AT MY RIGHT HAND, 35 UNTIL I MAKE YOUR ENEMIES A FOOTSTOOL FOR YOUR FEET."
Hebrews 10:12-13 “but He, having offered one sacrifice for sins for all time, SAT DOWN AT THE RIGHT HAND OF GOD,
13 waiting from that time onward UNTIL HIS ENEMIES BE MADE A FOOTSTOOL FOR HIS FEET.”