The phrase ‘as a thief’ regarding the Lord’s Return, is seen twice in the New Testament, not once.
‘As a thief in the night‘ is for unbelievers living during the Tribulation period and after the Tribulation period. This passage is not about the Rapture event. Nor does it apply to believers.
With the Rapture no one knows the date of the event. It is imminent. But here, unbelievers do not know, but believers WILL KNOW.
Once The Pre-Tribulation Rapture event happens, the Tribulation Period starts. During the Tribulation Period on Earth. the 144,000 Jewish Evangelists for Christ will know the exact date of Christ’s return. We know exactly the day that the Second Coming will occur and it occurs exactly 1,260 days after the Abomination of Desolation during the Tribulation Period. And it occurs exactly 1,290 days after the Antichrist issues the decree to stop the Jewish sacrifices at the Temple.
That is a very time specific prophecy from Daniel. So for THE BELIEVING survivors of the Tribulation Period, they are anticipating the Lord’s coming on a specific date!
THE UNBELIEVERS who sided with Antichrist will believe his great deception and will think Christ already is here ; the antichrist. To THEM it will come as A THIEF in the night but not for believers.
Paul is talking about the same event as Jesus in Matthew 24:43,
“But know this, that if the goodman of the house had known in what watch THE THIEF would come, he would have watched, and would not have suffered his house to be broken up.” (Matthew 24:43 KJV)
These two passages are about the Second Coming; not the Pre-Trib Rapture.
Paul tells about the Pre-Tribulation Rapture in another earlier passage and it too will happen. But this passage is about the Second Coming Event.
1 Thessalonians 5
“1 But of the times and the seasons, BRETHREN, YE have NO NEED that I write UNTO YOU.
2 For YOURSELVES KNOW PERFECTLY that the DAY OF THE LORD so cometh as A THIEF in the night.”
DON: This group Does Know The Time. Believers will know. Who will not know?
“3 FOR WHEN THEY shall say, Peace and safety; then sudden destruction cometh upon them, as travail upon a woman with child; and they shall not escape.”
DON: The word THEY is used not the word YOU. These are unbelievers in the first part of the Tribulation Period. A peace treaty by Antichrist will have those unbelieving left behind at Rapture saying ‘peace and safety’.
“4 BUT YE, BRETHREN, ARE NOT in darkness, that that day should overtake YOU as a thief.”
DON : For YOU believers it will NOT take you surprise as a thief! This is talking about believers.
“5 YE ARE all the children of light, and the children of the day: we are not of the night, nor of darkness.
6 Therefore let US not sleep, AS DO OTHERS; but LET US watch and be sober.
7 FOR THEY that sleep sleep in the night; and they that be drunken are drunken in the night.”
DON: Switches to THEY, that is unbelievers.
“8 But LET US, who are of the day, be sober, putting on the breastplate OF FAITH and love; and for an helmet, THE HOPE OF SALVATION.”
DON: Switches back to believers. The Rapture is our blessed hope! Believers are looking for the Rapture and not the Antichrist in the Tribulation Period.
We who believe on Christ, in this age of grace, will be Raptured before the Tribulation and will return WITH CHRIST for the Second Coming event. Paul encourages these believers, and us, living in this dispensation of God’s Grace that we will be raptured before the Tribulation.
“9 For God hath not appointed US TO WRATH, but to obtain salvation by our Lord Jesus Christ,”
DON: Wrath is God’s wrath and will be poured out to those living in the Tribulation Period, not our current dispensation of Grace.
“10 Who died for us, that, whether we wake or sleep, WE should live together WITH HIM. 11 Wherefore COMFORT YOURSELVES together, and edify one another, even as also YE DO.”
Apparently the believers Paul writes to were thinking if they died before the Rapture they will miss it and some were confused about the two separate events: The Rapture and The Second Coming.
Paul is comparing and contrasting so they know they are two events and not one. The Rapture is our blessed hope. We meet the Lord ‘in the air’ to our new home; The New Jeruslaem prepared for the Bride of Christ. The completion of our now perfect Spirit (Colossians 2) united with our new glorified resurrected body which has no more sin problem.
At The Second Coming of Christ returning to Earth to begin His 1000 year reign in the Kingdom Age, we return with Christ and Christ lands ‘on the Earth’ to setup the 1000 year Kingdom Age on Earth.
The Pre-Tribulation Rapture is Scriptural but 1 Thessalonians 5 is about The Second Coming.