There are many people going back and forth over a pre-tribulation rapture versus a post-tribulation rapture (Daniel prophesied this, "many will go to and fro.") Rather than take a few verses, or worse, one verse, and build a doctrine out of it, the entire bible must be looked at. Also one must look at God and His work with humans since the course of time began. But first, to answer questions about the rapture, one needs to ask what is the Tribulation? GotQuestions.org has an answer:
"First, it is important to recognize the purpose of the tribulation. According to Daniel 9:27, there is a seventieth “seven” (seven years) that is still yet to come. Daniel’s entire prophecy of the seventy sevens (Daniel 9:20-27) is speaking of the nation of Israel. It is a time period in which God focuses His attention especially on Israel. The seventieth seven, the tribulation, must also be a time when God deals specifically with Israel. While this does not necessarily indicate that the church could not also be present, it does bring into question why the church would need to be on the earth during that time."
"The primary Scripture passage on the rapture is 1 Thessalonians 4:13-18. It states that all living believers, along with all believers who have died, will meet the Lord Jesus in the air and will be with Him forever. The rapture is God’s removing His people from the earth. A few verses later, in 1 Thessalonians 5:9, Paul says, “For God did not appoint us to suffer wrath but to receive salvation through our Lord Jesus Christ.” The book of Revelation, which deals primarily with the time period of the tribulation, is a prophetic message of how God will pour out His wrath upon the earth during the tribulation. It seems inconsistent for God to promise believers that they will not suffer wrath and then leave them on the earth to suffer through the wrath of the tribulation. The fact that God promises to deliver Christians from wrath shortly after promising to remove His people from the earth seems to link those two events together.
"Another crucial passage on the timing of the rapture is Revelation 3:10, in which Christ promises to deliver believers from the “hour of trial” that is going to come upon the earth. This could mean two things. Either Christ will protect believers in the midst of the trials, or He will deliver believers out of the trials. Both are valid meanings of the Greek word translated “from.” However, it is important to recognize what believers are promised to be kept from. It is not just the trial, but the “hour” of trial. Christ is promising to keep believers from the very time period that contains the trials, namely the tribulation. The purpose of the tribulation, the purpose of the rapture, the meaning of 1 Thessalonians 5:9, and the interpretation of Revelation 3:10 all give clear support to the pre-tribulational position. If the Bible is interpreted literally and consistently, the pre-tribulational position is the most biblically-based interpretation."
Jack Kelley has answered the pre-vs-post trib many times in his "Ask a Bible Teacher" forum. In the interest of not re-inventing the wheel, I will excerpt some of his excellent work. For more answers to bible questions on this, or any topic, go to GraceThruFaith. Here's Jack-
"There are many indications, both explicit and implicit, that require a pre-trib rapture. To interpret it any differently means the reader has either departed from a strict literal interpretation or worse, has actually re-interpreted Scripture. Since there’s only one rapture of the Church there cannot be prophecies that support both pre and post trib raptures. One of the positions has to be the result of human misunderstanding. So far in my experience, prophecies put forward to support the post trib position have either been speaking to Israel, not the Church, or speaking about the 2nd Coming, not the Rapture."
"Suffering for our faith has often been a part of the Christian Life. In John 16:33 Jesus said that we’d have tribulation in our lives. Over 3000 people die every day in this world just because they believe in Jesus. But the Great Tribulation is something different. Jesus said there has never been anything like it in the history of the world, nor would there ever be again. He said that if He didn’t put an end to it not a single human would survive. (Matt. 24:21-22). And he said that He’d keep His church out of it. (Rev. 3:10) "
So if pre-trib is the biblically correct view, and if Jesus said He would keep the Church out of it, where does this post-tribulation view come from?
Jack Kelley said: "There are lots of anti pre-trib viewpoints around, and the only explanation is that those who promote them don’t really understand what went on at the cross. At some level they believe the Church should endure the great Tribulation because it needs to be purified, when in fact the Church was purified at the cross, becoming as righteous as God Himself in His eyes (2 Cor 5:17,21) They begin with the conviction that there is no pre-trib rapture and then pick and choose verses that when looked at all by themselves without the benefit of context, can be used to support their position."
For example, "The phrase “Last Trump” has no demonstrable connection to either the 7th trumpet judgment, as some claim, or to the 2nd Coming. It refers to the trumpet of God mentioned in 1 Thes. 4:16. "
Continuing with Jack Kelley's explanation in a different vein, "Mark 13:24-27 says that Jesus will gather the elect at the time of His Coming. But it also says that some will be in Heaven (the Church) and some will be on Earth (Tribulation believers)."
"Please remember that for reasons of secrecy explained in 1 Cor. 2:7-8, Jesus never spoke about the Rapture at all, nor did He teach it to His disciples. That’s why you won’t find in mentioned in the Gospels. We only see hints of it, as in Mark 13, because we already know about it. The Doctrine of the Rapture was first disclosed on Earth by Paul in 1 Thes. 4:15-18 nearly 20 years after the cross."
"1 Thes.4:13-18 while introducing the rapture doctrine doesn’t indicate pre or post trib. You have to infer its timing from other passages like 1 Thes. 1:9 and 5:9, 2 Thes. 2 Rev 3:10, Isaiah 26:19-21. I don’t think it can be the 2nd coming because Jesus doesn’t come to earth in a visible return in glory but draws us up to be with Him in the Air in fulfillment of John 14:1-3." "1 Thessalonians 4:16-17 is describing the Rapture, not the 2nd coming. We know this because the church is going up to Heaven to meet the Lord where He is. At the 2nd Coming the Lord comes to Earth to meet people where they are."
A rebuttal to the most oft-cited post-trib "supporting" verse is here:
And now you know what is holding him back, so that he may be revealed at the proper time. For the secret power of lawlessness is already at work; but the one who now holds it back will continue to do so till he is taken out of the way. And then the lawless one will be revealed, whom the Lord Jesus will overthrow with the breath of his mouth and destroy by the splendor of his coming. (2 Thes. 2:6-8)
An excerpt to "What's behind the Post-trib view?"
"In my experience most people who believe in the post trib rapture don’t do so because of what the Bible says. It’s not difficult to demonstrate that verses they use to support their position are either taken out of context, or misinterpreted. I think the reason they cling to their post trib position is that deep down they believe the Church deserves to be judged and purified and they want to believe it will happen." More here.
The rapture is an event that will take place in the twinkling of an eye. The Tribulation is "the hour of trial"- a lengthy period of judgment in which God pours out His wrath on the rebellious people. Post-trib view cannot explain the imminence of the rapture since the Tribulation is a scheduled series of events that are prophesied down to the last day. Contrastingly, the rapture is an event that was so secret it was not revealed as doctrine until 20 years after the cross, and its exact moment of fulfillment is still a secret today.
"In 1 Thes. 1:10 Paul wrote that Jesus would rescue us from the coming wrath. The Greek word for rescue in the verse means to deliver, or draw to oneself. The word for from denotes a separation of time and distance. So the Lord will draw us to Himself to distance us from the time and place of the wrath to come. In 1 Thes. 5:9 he said the Church was not appointed to suffer wrath. In Rev. 3:10 the Lord promised to keep us from the “hour of trial” that’s coming upon the whole world. A different Greek word for from us used there. It means out of the place, time, or cause of the event being referenced. So here His promise is to keep us out of the time and place of His wrath, because we’re not the cause of it. Put it all together and it says we won’t be here for any of it."
Or you can go to GraceThruFaith and search keyword rapture for plenty more explanations why the pre-trib doctrine is the only correct rapture stance.