36"No one knows about that day or hour, not even the angels in heaven, nor the Son,[6] but only the Father. 37As it was in the days of Noah, so it will be at the coming of the Son of Man. 38For in the days before the flood, people were eating and drinking, marrying and giving in marriage, up to the day Noah entered the ark; 39and they knew nothing about what would happen until the flood came and took them all away. That is how it will be at the coming of the Son of Man. 40Two men will be in the field; one will be taken and the other left. 41Two women will be grinding with a hand mill; one will be taken and the other left.
42"Therefore keep watch, because you do not know on what day your Lord will come. 43But understand this: If the owner of the house had known at what time of night the thief was coming, he would have kept watch and would not have let his house be broken into. 44So you also must be ready, because the Son of Man will come at an hour when you do not expect him.
Here is the link to Matthew, Chapter 24. If the link doesn't work, of course you can look it up in your own Bible.
The whole passage is not a reference to rapture but to the final coming of Christ. Christ will come once to conquer the anitchrist and hold court for the general judgment. This is the doctrine that the primitive church taught and believed.
All else is innovative, a new belief formulated late in the 1800's. Pre- and post- millenialists teach that Jesus will come not once, but two or even three times. This is the new doctrine that the early fathers of the church did not teach - and by corollary, that Jesus did not teach. Jesus will not come once to take some away, then come again to rule for one thousand years, and then depart to return again after a final tribulation to end the world.
He will come once, at the end of time.