The apostle Paul explains what happens when a believer dies: “But I do not want you to be ignorant, brethren, concerning those who have fallen asleep, lest you sorrow as others who have no hope. For if we believe that Jesus died and rose again, even so God will bring with Him those who sleep in Jesus” (1 Thessalonians 4:13-14). Here, we know the term "fallen asleep" is referring to death because he contrasts those who are asleep with "those who are alive and remain" (1 Thessalonians 4:15; compare Revelation 6:9-11). Then those in the faith who are still alive when Christ returns will be resurrected in the next instant after Christ returns (1 Thessalonians 4:17).

What is the kind of life that they will be resurrected to? It is life as a spirit being, rather than as a physical being (1 Corinthians 15:42-51; compare 1 Thessalonians 4:13-17, Revelation 11:15).

What about those who didn’t die “in Christ”? Are these people unsaved and condemned to burn forever in torment? No. For people not in this first resurrection, there is a second resurrection. It is described in Revelation: “I saw the souls of those who had been beheaded for their testimony about Jesus and for proclaiming the word of God . . . They all came to life again, and they reigned with Christ for a thousand years. This is the first resurrection. (The rest of the dead did not come back to life until the thousand years had ended.)” (Revelation 20:4-5, New Living Translation).

Notice the phrase “the rest of the dead.” Who are these people who are resurrected at the end of the thousand years? Quite simply, they are all those who are not in the first resurrection. So who is that? It is the vast majority of humanity that has ever lived, who never truly knew or understood who God is, or what his plan for man is. Most significantly, notice that the Bible says these people will live again!

Jesus Christ spoke about this second resurrection as well. In Matthew 12:38-42, Christ condemns the religious leaders of His day, saying: “The men of Nineveh will rise up in the judgment with this generation and condemn it, because they repented at the preaching of Jonah; and indeed a greater than Jonah is here. The queen of the South will rise up in the judgment with this generation and condemn it, for she came from the ends of the earth to hear the wisdom of Solomon; and indeed a greater than Solomon is here.” Christ says these people will be resurrected (the word for "rise up" here is the same root word for resurrection we read earlier in Revelation 20:5).

What an amazing concept! People who did not know Christ will indeed stand up once more, in a physical life, and have an opportunity to understand who God and Christ are and what their plan for all humanity is. The only way for this to be possible—for people who lived literally many hundreds of years apart to live again at the same time—is for God to resurrect all of them at the same time.

The Scriptures are plain about the fact that all people have only one chance at salvation. However, a second chance at life is not the same as a second chance at salvation. Coming to life again will enable them to have their only chance for salvation. To understand more about what happens after death, read What Happens After Death? and Heaven and Hell: What Does the Bible Really Teach?