First a Lamb, later a Lion
One thousand years before Jesus was born, David penned his famous prophecy of the Messiah in Psalm 110, describing a future ruler who would arrive on the earth to put down and subdue every enemy.
Psalms 110:1c The LORD said to my Lord, “Sit at My right hand, Till I make Your enemies Your footstool.”
First the Messiah would come to us as a humble servant and offer up His perfect life for all our sins. Then, at the end of the age, He will return a second time–as a Mighty King, to take His rightful place as the ruler of the universe. This is only right, since the book of Colossians describes Jesus as the agent of creation and the One for whom all things were made.
For by Jesus all things were created that are in heaven and that are on earth, visible and invisible, whether thrones or dominions or principalities or powers. All things were created through Him and for Him. And He is before all things, and in Him all things consist. –Colossians 1:16-17
The fact that this prophecy from Psalm 110:1 is applicable to Jesus as the Messiah is confirmed by Paul’s nearly identical usage of the same language, in the book of 1 Corinthians 15:25.
1 Corinthians 15:25 For He (Jesus) must reign till He has put all enemies under His feet.
Psalms 110:1b The LORD said to my Lord, “Sit at My right hand, Till I make Your enemies Your footstool.”
The Bible describes Jesus Christ as reigning over the whole earth until all of His enemies are placed under his footstool. This term is first observed in the Old Testament Book of 1 Kings, where David is described as reigning as king until the Lord put His foes under the soles of His feet. The idea here is that all of His enemies will be defeated and subdued.
1 Kings 5:3 You know how my father David could not build a house for the name of the LORD his God because of the wars which were fought against him on every side, until the LORD put his foes under the soles of his feet.
Psalm 110 is one of the most frequently quoted texts in the New Testament—recited in the four Gospels, the Book of Acts, many of Paul’s epistles, the Book of Hebrews, and the writings of Peter.
Psalm 72, also written by David–as a description of the coming reign of the Messiah: All kings shall fall down before Him; All nations shall serve Him.
Psalms 72:1-11 Give the king Your judgments, O God, And Your righteousness to the king’s Son. He will judge Your people with righteousness, And Your poor with justice. The mountains will bring peace to the people, And the little hills, by righteousness. He will bring justice to the poor of the people; He will save the children of the needy, And will break in pieces the oppressor. They shall fear You As long as the sun and moon endure, Throughout all generations. He shall come down like rain upon the grass before mowing, Like showers that water the earth. In His days the righteous shall flourish, And abundance of peace, Until the moon is no more. He shall have dominion also from sea to sea, And from the River to the ends of the earth. Those who dwell in the wilderness will bow before Him, And His enemies will lick the dust. The kings of Tarshish and of the isles Will bring presents; The kings of Sheba and Seba Will offer gifts. Yes, all kings shall fall down before Him; All nations shall serve Him.
The greatest enemy: satan, has already been placed under Jesus’ footstool (defeated). Though the Lord will not return to establish His kingdom before all the nations until later, He has already secured the right to rule over the nations by His resurrection from the dead. The purpose of Jesus delay in returning—is to allow all those who will receive Him the opportunity to be saved, before He arrives.
2 Peter 3:3, 4, 9 knowing this first: that scoffers will come in the last days, walking according to their own lusts, 4 and saying, “Where is the promise of His coming? 9 The Lord is not slack concerning His promise, as some count slackness, but is longsuffering toward us, not willing that any should perish but that all should come to repentance.
The complete fulfillment of this 144th Old Testament Prophecy will occur when Jesus does return to earth, at the end of the seven-year Tribulation. All the nations will be gathered before Him, and He will determine which nations will be permitted to go into the one thousand-year reign of the Messiah and which nations will be cast out into outer darkness.
Matthew 25:31-32 When the Son of Man comes in His glory, and all the holy angels with Him, then He will sit on the throne of His glory. All the nations will be gathered before Him, and He will separate them one from another, as a shepherd divides his sheep from the goats.
The nations which persecuted Israel during the seven-year Tribulation period will be cast out. The nations which gave assistance to Israel and helped the Jews, will enter into the kingdom age (Matthew 25:33-46).
At that time, all of the enemies of the Lord will be placed in submission to Him and this prophecy will come to pass: Till I make Your enemies Your footstool.
A secular usage of this term
This term, make your enemies your footstool, also appears in a thirteenth century reference to an Assyrian king called Tukulti-Ninurta, the First. He put his foot on the neck of the kings to whom he had conquered as a symbol to them that they had been subdued. They were said at this point to be “his footstool.”
Today, we think of Jesus as a meek and gentle Savior who would harm no one. When He returns to the earth at the end of the seven-year Tribulation, He will be a mighty conquering King, who will rule all the nations by force. To those who love Him and have already submitted to His Lordship, their knees will bow to Him willingly. For those who have refused to submit to the authority of Jesus during their life, should they survive the terrors of the seven-year Tribulation, they will be forced to bow their knees to Jesus’ rulership.
Therefore God also has highly exalted Jesus and given Him the name which is above every name, that at the name of Jesus every knee should bow, of those in heaven, and of those on earth, and of those under the earth. —Philippians 2:9-10
All the enemies of Jesus will be placed as His footstool, and He will rule over all people and nations. Imagine the look on the faces of those who stubbornly refuse to acknowledge Jesus today, or who deny that He is anything more than a myth, when they realize that He is the Lord of the entire Universe.
In the Book of Acts Chapter 2, Peter stands before the crowd on the day of Pentecost and proclaims the greatness and right to rule that Jesus alone possesses:
Acts 2:32-36 This Jesus God has raised up, of which we are all witnesses. Therefore being exalted to the right hand of God, and having received from the Father the promise of the Holy Spirit, He poured out this which you now see and hear. For David did not ascend into the heavens, but he says himself: “The LORD said to my Lord, ‘Sit at My right hand, Till I make Your enemies Your footstool.’ ” Therefore let all the house of Israel know assuredly that God has made this Jesus, whom you crucified, both Lord and Christ.
Peter confirms Jesus as the Messiah, the fulfillment of David’s words in Psalm 110:1
This once obstinate fisherman now acknowledges before all the nations gathered before him, that the object of David’s prophecy—was Jesus Christ, whom God has made both Lord and Christ.
 Albert Kirk Grayson (1972). Assyrian Royal Inscriptions: Volume I. Wiesbaden: Otto Harrassowitz. p. 108. §716.