With this in mind we need to read 1 Thessalonians 4:15: "For this we say unto you by the word of the Lord, that we that are alive, that are left unto the coming of the Lord, shall in no wise precede them that are fallen asleep" (ASV). This means that the dead believers will be resurrected first, and then the living believers will be raptured. It is not that we will be raptured first and then the dead ones will be resurrected. When will this occur? Verse 16 says, "For the Lord Himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first." The time that we will be raptured will be at the trumpet of God. Is this at the time of the first trumpet or of another trumpet? To answer this question we must read 1 Corinthians 15:52: "In a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed." This verse clearly says that we shall be changed at the last trumpet. It also says that the dead shall be raised at the last trumpet. This last trumpet is no doubt the seventh trumpet. All the dead believers will be resurrected and all the living believers will be raptured at the seventh trumpet. The last trumpet, of course, is sounded very close to the end of the tribulation. This strongly indicates that not all of the believers will be raptured before the tribulation.
A further indication of this fact is found in 2 Thessalonians 2:1-5. Verse 3 says, "Let no man deceive you by any means: for that day shall not come, except there come a falling away first, and that man of sin be revealed, the son of perdition." The "son of perdition" is the Antichrist. "That day" is the day of the Lord's coming. This verse tells us that the day of the Lord's coming cannot occur except the Antichrist come first. Our gathering together unto the Lord cannot precede the appearance of the man of sin, the Antichrist. These two points, the time of the seventh trumpet and the appearing of the man of sin, prove that not all of the Christians will be raptured before the tribulation.
However this does not mean that all of the Christians will be here at the time of 1 Thessalonians 4 and 1 Corinthians 15. The exceptions are the firstfruit which are taken away beforehand. This is seen in Matthew 24 where two are working in a field, but one is taken and one is left. Two are grinding at home, but one is taken and one is left. This is a parable which indicates that two Christians are there working together. One will be raptured, and the other will be left. This is the pure Word of the Bible. Some of the saints who will be matured prior to others will be taken away. When they are taken away, it will be like precious things being stolen. Revelation 3:3 indicates that the Lord will come as a thief to steal something. When we are not aware of Him, He will come, not to steal junk but precious things. Only those who are matured in life and transformed in soul will be precious enough for the Lord to steal.