A couple myths naysayers will repeat (because they've been taught them, not because they've actually researched them) in argument against a pre-Tribulation Rapture:
"The Rapture was not taught until the 1800's."
In Grant Jeffrey's book "Triumphant Return", he writes that about 373 AD Ephraem taught in a sermon that there was a pre-tribulation rapture. This writing can be found in Ephraem's sermon "On the Last Times, the Antichrist, and the End of the World.", Ephraem said in this sermon, "For the saints and Elect of God are gathered, prior to the tribulation that is to come, and are taken to the Lord lest they see the confusion that is to overwhelm the world because of our sins". Ephraem also taught in this same sermon that the war of Gog and Magog in Ezekiel 38-39 would precede the tribulation and he taught the imminent return of Jesus.
"There is no 'secret rapture' of the Church."
Of course not, and there is nothing in Scripture that describes it as "secret" either.
The rapture will not be secret. In fact the world has been informed that it will happen through many popular writings like the "Left Behind" series. The rapture event itself will be known to all who will witness the missing people, although the government will certainly come up with some cockamamie excuse for us being gone. The "New Age" pagans have even pre-prepared explanations for the rapture in some of their writings.
Now for some proofs of the pre-trib rapture:
Revelation 19:11-21 doesn't mention a resurrection. The rapture is a resurrection of those "in Christ" (1 Thess. 4:13-18). Isn't it a little bit odd that in Rev. 19:11-21, which is the clearest picture of the second coming of Christ, there is no mention of a resurrection? The rapture will be the biggest event since the resurrection of Jesus where hundreds of millions of Christians will be resurrected and translated, yet there isn't any mention here. Don't you think it deserves at least one verse? The rapture isn't mentioned because it doesn't happen at the second coming.
The Known Day and the Unknown Day. Concerning the return of Jesus, the Bible presents a day we can't know and a day we can know. Matthew 25:13 says Jesus will return at an unknown time, while Revelation 12:6 says the Jews will have to wait 1,260 days for the Lord to return. The 1,260 days begins when the Antichrist stands in the Temple and declares himself to be God (Matt. 24:15-21, 2 Thess. 2:4) This event will take place at the mid-point of the seven year Tribulation (Dan 9:27). The Antichrist has authority to rule for 42 months, which is 1,260 days (Rev. 13:4) and will be destroyed by Jesus at His second coming (Rev. 19:20, 2 Thess. 2:8). The known and unknown days must happen at different times, meaning they are two separate events.
A door open in heaven (Revelation 4:1). The door in heaven is opened to let John into heaven. He is told by the angel, "Come up here." We believe John's call into heaven is prophetic of the Church being caught up at the rapture (see proof #6). In Revelation 19:11, heaven is opened again, this time to let the armies which are already in heaven out. This is the Church, which has been raptured at a previous time, following Jesus out of heaven at the second coming.
The 24 elders have their crowns. After John is called up into heaven, he sees the 24 elders with their crowns (Rev. 4:4-10). We know that Christians will receive their rewards (crowns) at the rapture (2 Tim. 4:8, 1 Pet. 5:4). We will be repaid at the resurrection of the righteous (Luke 14:14). The elders couldn't receive their crowns unless the resurrection (rapture) has taken place.
Kept from the hour of testing (Rev. 3:10). Revelation 3:10 says we will be kept out of the hour of testing which will come upon the whole earth (the Tribulation). Some have wrongly believed "keep" means to keep through, or protect through the Tribulation. Suppose you approach a high voltage area with a sign that says, "Keep Out." Does that mean you can enter and be protected? No, it means you are forbidden from entering the area. But this verse also says He will keep us from the hour of testing. It is not just the testing, but the time period. If a student is excused from a test, he still may have to sit in the class while others take the test. But if he is excused from the hour of testing, he can go home. The Church will be called home before the hour of testing.
Both wicked and righteous both can't be taken first. First Thessalonians 4:13-17 says the righteous are taken and the wicked are left behind. Matthew 13:30, 49 says the wicked are taken first and righteous are left behind. This points to two separate events, the rapture and the second coming.
Jesus returns from the wedding. When Jesus returns to earth at the second coming, He will return from a wedding (Luke 12:36). At the rapture, Jesus is married to His bride, the Church. After the wedding, He will return to earth.
Who will populate the Millennium? If the rapture occurs at the second coming and the wicked are cast into hell at that time, who will be left to populate the millennium? Only people in their natural (non-resurrected) bodies will be able to have children (Matt. 22:30). With a Pre-Tribulation rapture, the people saved after the rapture who are alive at the second coming will populate the earth during the Millennium
Those are just a few. there are more.