1 Thessalonians 4:13-18 ESV
But we do not want you to be uninformed, brothers, about those who are asleep, that you may not grieve as others do who have no hope.  For since we believe that Jesus died and rose again, even so, through Jesus, God will bring with him those who have fallen asleep.  For this we declare to you by a word from the Lord, that we who are alive, who are left until the coming of the Lord, will not precede those who have fallen asleep.  For the Lord himself will descend from heaven with a cry of command, with the voice of an archangel, and with the sound of the trumpet of God. And the dead in Christ will rise first.  Then we who are alive, who are left, will be caught up together with them in the clouds to meet the Lord in the air, and so we will always be with the Lord.  Therefore encourage one another with these words.
The Saints were worried for their brothers and sister dying before Jesus Christ came back. Obviously this passage does not say the word rapture, but sets up the pretense which that word maintains. Those who have passed will be risen first. This sets up the disagreement that the rapture and the day of the Lord are two different things.
1 Thessalonians 5:2 ESV
For you yourselves are fully aware that the day of the Lord will come like a thief in the night.
1 Thessalonians 5:4 ESV
But you are not in darkness, brothers, for that day to surprise you like a thief.
The day of the Lord (not the rapture) will come like a thief in the night for those who do not believe. Those who are awaiting the day of the Lord will know absolutely how close it is when it comes. No they won’t won’t know the day or hour. But they will know by the season. They will know by the events going on. Now the events of the tribulation will be so pressing and that there will be no date calculated on the calendar.
2 Thessalonians 2:2-3 ESV
not to be quickly shaken in mind or alarmed, either by a spirit or a spoken word, or a letter seeming to be from us, to the effect that the day of the Lord has come.  Let no one deceive you in any way. For that day will not come, unless the rebellion comes first, and the man of lawlessness is revealed, the son of destruction,
Now the day of the Lord will not come until after the anti christ stops the sacrifices happening in the new temple built. He will seat himself on the throne in the temple. He will reveal himself completely.
Daniel 9:27 ESV
And he shall make a strong covenant with many for one week, and for half of the week he shall put an end to sacrifice and offering. And on the wing of abominations shall come one who makes desolate, until the decreed end is poured out on the desolator.”
The Thessalonians were troubled thinking that the day of the Lord had past and missed him. This seems to be in line with much of the thinking today that we who believe today will miss the tribulation but consider this verse of those who are in heaven awaiting the day of the Lord for judgement to come to those who have murdered the Saints.
Revelation 6:9-11 ESV
When he opened the fifth seal, I saw under the altar the souls of those who had been slain for the word of God and for the witness they had borne.  They cried out with a loud voice, “O Sovereign Lord, holy and true, how long before you will judge and avenge our blood on those who dwell on the earth?”  Then they were each given a white robe and told to rest a little longer, until the number of their fellow servants and their brothers should be complete, who were to be killed as they themselves had been.
So the complete number of the martyrs for christ must be accounted for before the day of the Lord that comes like a thief to be gathered together at the end of the tribulation.
Revelation 16:14-16 KJVS
For they are the spirits of devils, working miracles, which go forth unto the kings of the earth and of the whole world, to gather them to the battle of that great day of God Almighty.  Behold, I come as a thief. Blessed is he that watcheth, and keepeth his garments, lest he walk naked, and they see his shame.  And he gathered them together into a place called in the Hebrew tongue Armageddon.
Now I understand the preferred theology that pre tribulation gives. No one likes the idea of suffering or being murdered for their faith. Yet Jesus told us this would happen. We would be murdered for his name. He said that we would have to endure to show our faith be true. To those who would say we are not ment to endure God’s wrath which will be poured out on the earth, that is true. Just as much as God’s wrath was not poured out on the children of Israel in Egypt. The enslavement of Israel in Egypt is the same as our bondage in this world. Instead of pharoh being the man trying everything possible to keep us enslaved to sin it is Satan who will be fighting to stop us from leaving sin behind. His time will be short.
Revelation 16:2 ESV
So the first angel went and poured out his bowl on the earth, and harmful and painful sores came upon the people who bore the mark of the beast and worshiped its image.
So you see that even in time of judgement and trial God remains faithful to those who have not sided with the anti christ. Those who remain faithful will be preserved just as he preserved the Israelites in Egypt. Just as Job was rewarded when Satan was allowed to test his faith he had much like our faith in America, Jobs faith had never been tested like when Satan truly tested it nor has our faith in America been tested like it will be in the tribulation. We will be rewarded for our faithfulness when the hedge is removed. Be strong keep the full armor of faith. Because it will sound better to curse God and die than to endure these trials. But as so this cup falls perhaps to our generation like it did to Jesus. Is it not written that it must come to pass?
Matthew 25:1-13 ESV
“Then the kingdom of heaven will be like ten virgins who took their lamps and went to meet the bridegroom.  Five of them were foolish, and five were wise.  For when the foolish took their lamps, they took no oil with them,  but the wise took flasks of oil with their lamps.  As the bridegroom was delayed, they all became drowsy and slept.  But at midnight there was a cry, ‘Here is the bridegroom! Come out to meet him.’  Then all those virgins rose and trimmed their lamps.  And the foolish said to the wise, ‘Give us some of your oil, for our lamps are going out.’  But the wise answered, saying, ‘Since there will not be enough for us and for you, go rather to the dealers and buy for yourselves.’  And while they were going to buy, the bridegroom came, and those who were ready went in with him to the marriage feast, and the door was shut.  Afterward the other virgins came also, saying, ‘Lord, lord, open to us.’  But he answered, ‘Truly, I say to you, I do not know you.’  Watch therefore, for you know neither the day nor the hour.
In closing argument. When the day of the lord comes, the doors to the kingdom will be shut. Therefore there will be no more grace for those who do not believe. There will be no more chance for redemption. There will not be any more time to repent and the gates to heaven will be shut. When the trial of humanity, the greatest trying of faith, we will be tested. For those who mock their hearts will be hardened. Their minds deceived, their bodies given to the lusts of their flesh. Those who are on the fence will have a choice. Thus the tribulation will be the last chance for salvation before the day of the lord. If we are to be taken before the tribulation then praise the Lord, however Lot was taken from Sodom and Gomorrah as the city was destroyed, so too will be the day of the Lord. Today is the day to prepare with enough oil to make it to the day of the lord whether you get there in life or death. The message is two fold for if you die without faith or go into these times with dead faith the time to buy more oil is gone from you.