The first resurrection of the dead, POST TRIB.

Rev. 20:4 Then I saw thrones, and they sat on them, and judgment was given to them. And I saw the souls of those who had been beheaded because of their testimony of Jesus and because of the word of God, and those who had not worshiped the beast or his image, and had not received the mark on their forehead and on their hand; and they came to life and reigned with Christ for a thousand years. 5 The rest of the dead did not come to life until the thousand years were completed. This is the first resurrection. 6 Blessed and holy is the one who has a part in the first resurrection; over these the second death has no power, but they will be priests of God and of Christ and will reign with Him for a thousand years.

We read Revelation 20:4-6 and see that martyrs of the Great Tribulation, overcomers of the 666 era, are given prominence as they come into the glory. They head up the parade of all the saints who belong to Christ who come up from their graves in the Resurrection, which John is clearly told is the First Resurrection. So the Resurrection of the righteous dead comes after the Great Tribulation.

1 Corin. 15:51 Behold, I tell you a mystery; we will not all sleep, but we will all be changed, 52 in a moment, in the twinkling of an eye, at the last trumpet; for the trumpet will sound, and the dead will be raised imperishable, and we will be changed. 53 For this [s]perishable must put on the imperishable, and this mortal must put on immortality.

1 Thes. 4:13 But we do not want you to be uninformed, brethren, about those who are asleep, so that you will not grieve as do the rest who have no hope. 14 For if we believe that Jesus died and rose again, even so God will bring with Him those who have fallen asleep in Jesus. 15 For this we say to you by the word of the Lord, that we who are alive and remain until the coming of the Lord, will not precede those who have fallen asleep. 16 For the Lord Himself will descend from heaven with a shout, with the voice of the archangel and with the trumpet of God, and the dead in Christ will rise first. 17 Then we who are alive and remain will be caught up together with them in the clouds to meet the Lord in the air, and so we shall always be with the Lord. 18 Therefore comfort one another with these words.

Paul knew that the dead preceed the living in the rapture. The dead go up in the first resurrection, the one that comes at the end of the tribulation. Even Martha knew it when she professed at the grave of Lazarus, John 11:24 Martha said to Him, “ I know that he will rise again in the resurrection on the last day.”