All Christians will be resurrected and in heaven before the great multitude, mentioned in Revelation 7:9, are gathered. The Church doesn't go through the great tribulation - these people do. The opportunity for gentiles to be grafted into the Israel of God, to become members of the body and bride of Christ, and to have a share in Christ's inheritance, ended when the Church was resurrected. The great multitude come to have belief and faith after that, and go through the great tribulation, and so are not part of the Christian Church. Remember Jesus' parable in Matthew 25 about the ten virgins - the five wise virgins make it into the marriage of the Lamb, but the foolish virgins miss out because they are not ready at the cut-off time; they were not prepared for Christ's return for the bride (Church).
Please quote the verses that you think say that, because that's not how I read it. In Revelation 7:13 John writes:
One of the elders answered, saying to me, “These who are arrayed in the white robes, who are they, and from where did they come?”
The elders are symbolic of the resurrected Church (Revelation 5:8-10). John knew who they represented, and he considered himself to be part of that Church (Revelation 1:5-6), yet he didn't know who the great multitude were. The elder had to explain who they were.
The great multitude are said to be in heaven, before God's throne ((Revelation 7:9,15) and will serve God in His temple. Those mentioned in chapter 20 are the resurrected dead, not members of the Church or great multitude, who have lived on the Earth (as humans) throughout the Millennial Age (1,000 year reign of Christ).
Mmmmh. Read again, it is simple:
To Daniel was said:
Dan. 7:
13 “I kept watching in the visions of the night, and look! with the clouds of the heavens, someone like a son of man was coming; and he gained access to the Ancient of Days, and they brought him up close before that One.
14 And
to him there were given rulership, honor, and a kingdom, that the peoples, nations, and language groups should all serve him. His rulership is an everlasting rulership that will not pass away, and his kingdom will not be destroyed.
...27 “‘And the kingdom and the rulership and the grandeur of the kingdoms under all the heavens were given
to the people who are the holy ones of the Supreme One. Their kingdom is an everlasting kingdom, and all rulerships will serve and obey them.’
Paul said:
1 Thess. 4:13 Moreover, brothers, we do not want you to be ignorant about those who are sleeping in death, so that you may not sorrow as the rest do who have no hope.
14 For if we have faith that Jesus died and rose again, so too God will bring with him those who have fallen asleep in death through Jesus.
15 For this is what we tell you by Jehovah’s word, that we the living who survive to the presence of the Lord will in no way precede those who have fallen asleep in death;
16 because the Lord himself will descend from heaven with a commanding call, with an archangel’s voice and with God’s trumpet, and those who are dead in union with Christ will rise first.
17 Afterward
we the living who are surviving will, together with them, be caught away in clouds to meet the Lord in the air; and thus we will always be with the Lord. 18 So keep comforting one another with these words.
John said:
Rev. 1:4 May you have undeserved kindness and peace from “the One who is and who was and who is coming,” and from the seven spirits that are before his throne,
5 and from Jesus Christ, “the Faithful Witness,” “the firstborn from the dead,” and “the Ruler of the kings of the earth.” To him who loves us and who set us free from our sins by means of his own blood—
6 and he made us to be a kingdom, priests to his God and Father—yes, to him be the glory and the might forever. Amen.
And celestial creatures sing to Jesus in heaven:
Rev. 5:9 (...) “You are worthy to take the scroll and open its seals, for you were slaughtered and with your blood you bought people for God out of every tribe and tongue and people and nation,
10 and
you made them to be a kingdom and priests to our God, and they are to rule as kings over the earth.”
The most you know what the Bible says in its whole, you got a better understanding of the whole thing; some call it
holistic understanding.