These "great multitude" of Rev.7:9 are not 'raptured' prior to the great tribulation, for no one is.
These are shown standing next to Christ during the future timing of the 1,000 years of Rev.20, an event that will occur after... the tribulation!
The parts in bold red are for during the 1,000 years future reign by Christ and His elect on earth:
Rev 7:13-17
13 And one of the elders answered, saying unto me, What are these which are arrayed in white robes? and whence came they?
14 And I said unto him, Sir, thou knowest. And he said to me, These are they which came out of great tribulation, and have washed their robes, and made them white in the blood of the Lamb.
15 Therefore are they before the throne of God, and serve Him day and night in His temple: and He That sitteth on the throne shall dwell among them.
16 They shall hunger no more, neither thirst any more; neither shall the sun light on them, nor any heat.
17 For the Lamb Which is in the midst of the throne shall feed them, and shall lead them unto living fountains of waters: and God shall wipe away all tears from their eyes.
KJV
The time when the Church will serve Christ involving a temple, is for Christ's future 1,000 years reign, which will involve the temple written of in Ezekiel 40 forward. That is when these will be before God's throne serving Him in His temple.
The time when they will no longer suffer hot or cold, nor thirst or hunger, is for after... Christ's return during His 1,000 years reign forward. Verse 17 goes with that, which is only about the 1,000 years timing when the River of the waters of life will manifest again on this earth like it did with God's Eden in Genesis 2.
So that's how we KNOW... those are not raptured prior to the great tribulation. Teaching that any of the saints stand before God's throne in Heaven, especially before or during the great trib, is a false teaching.