The Bible teaches that after Jesus ascended up into heaven, that He will return.
“So Christ was offered once to bear the sins of many. To those who eagerly wait for Him He will appear a second time, apart from sin, for salvation.”
On that day, a great resurrection will take place—some unto salvation, some unto condemnation.
“Do not marvel at this; for the hour is coming in which all who are in the graves will hear His voice and come forth–those who have done good, to the resurrection of life, and those who have done evil, to the resurrection of condemnation.”
“And this is the will of Him who sent Me, that everyone who sees the Son and believes in Him may have everlasting life; and I will raise him up at the last day.”
“He who rejects Me, and does not receive My words, has that which judges him–the word that I have spoken will judge him in the last day.”
1 Corinthians 15:52
“In a moment, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, and the dead will be raised incorruptible, and we shall be changed.”
1 Thessalonians 4:16-17
“For the Lord Himself will descend from heaven with a shout, with the voice of an archangel, and with the trumpet of God. And the dead in Christ will rise first. Then we who are alive and remain shall be caught up together with them in the clouds to meet the Lord in the air. And thus we shall always be with the Lord.”
This last passage says “the dead in Christ will rise.” that is a reference to those bodies of the faithful saints. Those bodies are resurrected and their spirits are reunited with their bodies. The faithful—whether alive or dead—will be with the Lord forever. But what will happen to the wicked, both dead and alive, on the “last day”?
2 Thessalonians 1:7-9
“And to give you who are troubled rest with us when the Lord Jesus is revealed from heaven with His mighty angels, in flaming fire taking vengeance on those who do not know God, and on those who do not obey the gospel of our Lord Jesus Christ. These shall be punished with everlasting destruction from the presence of the Lord and from the glory of His power.”
The day that Christ returns is the last day for planet earth. It will be destroyed.
2 Peter 3:10
“But the day of the Lord will come as a thief in the night, in which the heavens will pass away with a great noise, and the elements will melt with fervent heat; both the earth and the works that are in it will be burned up.”
To summarize: 1) Jesus descends; 2) the resurrection and judgment occur; 3) the earth is destroyed.