What is the marriage supper of the Lamb?
The Marriage Supper of the Lamb is the great celebration in Heaven that takes place after the vial judgments and just before Christ returns to earth, marking the eternal union of Jesus Christ, the Lamb, with His Church, the Bride.
The Marriage Supper of the Lamb is the great heavenly celebration that occurs after the vial judgments and before Christ's return to earth. It marks the eternal union between Jesus Christ, pictured as the Lamb, and His Church, pictured as His wife. It fulfills God's redemptive plan as the redeemed are united with Christ in perfect fellowship and joy.
Revelation 19:6-9 describes it this way: a great multitude cries Alleluia because the Lord God omnipotent reigns, declaring that the marriage of the Lamb has come and His wife has made herself ready. She is granted to be arrayed in fine linen, clean and white, which is called the righteousness of saints. Those who are called to this marriage supper are pronounced blessed, and these words are declared to be the true sayings of God.
The saints, clothed in that fine linen, take part in this feast as those who remained faithful and prepared for His coming. This event begins everlasting communion with Christ, a wedding feast that celebrates love, covenant, and victory. The Church, purified and glorified, enters eternal fellowship with the Lord and prepares to reign with Him in glory forever.
Right after this celebration, John falls at the feet of the one speaking to him to worship, but is corrected and told to worship God instead, since the speaker is a fellow servant who shares the testimony of Jesus. This shows that the glory revealed at the Marriage Supper belongs to all who remain faithful, for what that glorified being is, the saints shall be also. Following this joyous supper, the Battle of Armageddon then takes place, showing that the same Christ and Bride who rejoice at this feast go forth to war when the time comes.
The scriptures
And I heard as it were the voice of a great multitude, and as the voice of many waters, and as the voice of mighty thunderings, saying, Alleluia: for the Lord God omnipotent reigneth. Let us be glad and rejoice, and give honour to him: for the marriage of the Lamb is come, and his wife hath made herself ready. And to her was granted that she should be arrayed in fine linen, clean and white: for the fine linen is the righteousness of saints. And he saith unto me, Write, Blessed are they which are called unto the marriage supper of the Lamb. And he saith unto me, These are the true sayings of God. And I fell at his feet to worship him. And he said unto me, See thou do it not: I am thy fellowservant, and of thy brethren that have the testimony of Jesus: worship God: for the testimony of Jesus is the spirit of prophecy.
And I saw heaven opened, and behold a white horse; and he that sat upon him was called Faithful and True, and in righteousness he doth judge and make war. His eyes were as a flame of fire, and on his head were many crowns; and he had a name written, that no man knew, but he himself. And he was clothed with a vesture dipped in blood: and his name is called The Word of God. And the armies which were in heaven followed him upon white horses, clothed in fine linen, white and clean. And out of his mouth goeth a sharp sword, that with it he should smite the nations: and he shall rule them with a rod of iron: and he treadeth the winepress of the fierceness and wrath of Almighty God. And he hath on his vesture and on his thigh a name written, KING OF KINGS, AND LORD OF LORDS.
From the books
This answer is drawn from these passages in the Mary Banks Faith Library.