"21For then shall be great tribulation, such as was not since the beginning of the world to this time, no, nor ever shall be. 22And except those days should be shortened, there should no flesh be saved: but for the elect's sake those days shall be shortened."
https://biblehub.com/kjv/matthew/24.htm
"24But in those days, after that tribulation, the sun shall be darkened, and the moon shall not give her light, 25And the stars of heaven shall fall, and the powers that are in heaven shall be shaken. 26And then shall they see the Son of man coming in the clouds with great power and glory. 27And then shall he send his angels, and shall gather together his elect from the four winds, from the uttermost part of the earth to the uttermost part of heaven."
https://biblehub.com/kjv/mark/13.htm#14
"29Immediately after the tribulation of those days shall the sun be darkened, and the moon shall not give her light, and the stars shall fall from heaven, and the powers of the heavens shall be shaken: 30And then shall appear the sign of the Son of man in heaven: and then shall all the tribes of the earth mourn, and they shall see the Son of man coming in the clouds of heaven with power and great glory. 31And he shall send his angels with a great sound of a trumpet, and they shall gather together his elect from the four winds, from one end of heaven to the other."
https://biblehub.com/kjv/matthew/24.htm
"Post-Tribulation: This view sees the rapture as occurring simultaneous to the return of Christ at the end of the Tribulation."
https://www.thegospelcoalition.org/essay/the-rapture-question/