These verses are telling us that there's a great purging taking place of a group of people called the Multitude. They are of a great number from all nations, kindreds, people and tongues. They are from all over the world.
They have washed their robes and made them white in the blood of the Lamb. They come out of great tribulation such as not since the beginning of the world to this time, no nor ever shall be...Matthew 24:21,22.
Revelation 2:18-23(church of Thyatira) says that the angel has a few things against thee, because thou sufferest that woman Zezebel, which calleth herself a prophetess, to teach and to seduce my servants...Behold, I will cast her into a bed, and them that commit adultery with her into great tribulation..
It says that the Lord will cast "her" into a bed and them that commit fornication "with her" into great tribulation. This would probably be referring to the harlot church system. The "who are these" (spiritually) that are fornicating with this system. Those who do not love Truth and believing lies.
Let's look at their robes: (we will be seeing two groups of people with robes)
Revelation 6:9-11; "When he had opened the fifth seal, I saw under the altar the souls of them that were slain for the word of God, and for the testimony which they held: And they cried with a loud voice, saying, How long, O Lord, holy and true, dost thou not judge and avenge our blood on them that dwell on the earth? (11)and white robes were given unto every one of them; and it was said unto them, that they should rest yet for a little season, until their fellowservants also and their brethren, that should be killed as they were, should be fulfilled." This group had robes but were dirty, spotted and blemished. They had to wash them to get the defilement out. This represents unrighteousness but they have paid the price with their testimony.
Revelation 19:7,8; "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. (8) 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." This group is already wearing linen that is clean and white. This represents that they all ready are righteous.
Ephesians 5:27; "That he might present it to himself a glorious church, not having spot, or wrinkle, or any such thing: but that it should be holy and without blemish.
WHY WOULD THE MULTITUDE NEED TO WASH THEIR ROBES?
These are people that love God in their hearts but have been led astray.
Daniel 11:34,35; "Now when they shall fall, they shall be holpen with a little help: but many shall cleave to them with flatteries. And some of them of understanding shall fall, to try them, and to purge, and to make them white, even to the time of the end: because it is yet for a time appointed."
Daniel 12:10; "Many shall be purified, and made white, and tried; but the wicked shall do wickedly: and non of the wicked shall understand; but the wise shall understand."
Malachi 3:2,3; "But who may abide the day of his coming? and who shall stand when he appeareth? for he is like a refiner's fire, and like fullers' soap: and he shall sit as a refiner and purifier of silver: and he shall purify the sons of Levi, and purge them as gold and silver, that they may offer unto the Lord an offering in righteousness." Isaiah 1:25-27 says he will purge away the dross. dross is good for nothing. Silver must be heated to extreme tempature (tribulation)
The Lord has purchased us with His Blood. He paid the price. The people being addressed in these verses are not paid for, in fact it says they have to buy from the Lord, gold and white raiment. Which indicates they are lacking something.
Revelation 3:18-20; "I counsel thee to buy of me gold tried in the fire, that thou mayest be rich; and white raiment, that thou mayest be clothed, and that the shame of they nakedness do not appear; and anoint thine eyes with eyesalve, that thou mayest see. As many as I love, I rebuke and chasten: be zealous therefore, and repent. Behold, I stand at the door and knock: if any man hear my voice, and open the door, I will come in to him, and will sup with him, and he with me."
It seems that this is telling us that prior to this they were not walking in the truth and wake up in the great tribulation. He is now knocking to invite them to the supper since they missed the wedding. This story is also seen in Matthew 25 of the ten virgins. Five wise go into the wedding and are the bride(sealed) but the five foolish have to go buy to get into the supper. Isaiah 55:1; Song of Soloman 1:7.
This is all telling us some are in correct doctrine and some are believing in lies and we are to come out of the lies.
