I looked at the verses in question and wonder if you were referring to the part where Jesus speaks about the 'elect.'

'they will gather together His elect from the four winds, from one end of heaven to the other'

I watched a religious program where the preacher taught about the harvesting of fields back in Israel in those days.

First, they would harvest the first-fruits.

1st Corinthians 15:20 But now is Christ risen from the dead, and become the firstfruits of them that slept.

Jesus has been described as the first-fruits in the Bible.

Then, according to the program I watched, would come the main harvest (rapture).

They were commanded to always leave the four corners of their fields at harvest.

Leviticus 19:9 And when ye reap the harvest of your land, thou shalt not wholly reap the corners of thy field, neither shalt thou gather the gleanings of thy harvest.
10 And thou shalt not glean thy vineyard, neither shalt thou gather every grape of thy vineyard; thou shalt leave them for the poor and stranger: I am the LORD your God.

This preacher was saying that not everyone would be raptured. The 'elect' would be left behind. I'm guessing the reason would be to teach the unbelievers.

As it says in Revelation 7:14 And I said unto him, Sir, thou knowest. And he said to me, These are they which came out of great tribulation, and have washed their robes, and made them white in the blood of the Lamb.

How could those people make it through the tribulation without any believers to guide them? This is what the Bible says concerning the encounter between Philip and the eunuch.

Acts 8:30 And Philip ran thither to him, and heard him read the prophet Esaias, and said, Understandest thou what thou readest?
31 And he said, How can I, except some man should guide me? And he desired Philip that he would come up and sit with him.

So, the 'four winds' in Matthew could be a reference to the 'corners' of the field at harvest.

That's one explanation. We'll just have to wait and see how everything all comes together.

As to whether it will be pre-trib or not, I'm guessing pre-trib.

In Luke 17 it says
26 And as it was in the days of Noe, so shall it be also in the days of the Son of man. 27 They did eat, they drank, they married wives, they were given in marriage, until the day that Noe entered into the ark, and the flood came, and destroyed them all. 28 Likewise also as it was in the days of Lot; they did eat, they drank, they bought, they sold, they planted, they builded; 29 But the same day that Lot went out of Sodom it rained fire and brimstone from heaven, and destroyed them all. 30 Even thus shall it be in the day when the Son of man is revealed. 31 In that day, he which shall be upon the housetop, and his stuff in the house, let him not come down to take it away: and he that is in the field, let him likewise not return back. 32 Remember Lot's wife. 33 Whosoever shall seek to save his life shall lose it; and whosoever shall lose his life shall preserve it. 34 I tell you, in that night there shall be two men in one bed; the one shall be taken, and the other shall be left. 35 Two women shall be grinding together; the one shall be taken, and the other left. 36 Two men shall be in the field; the one shall be taken, and the other left.

So it appears that life will be going on as normal when it happens. I would think if the tribulation was in full force, they'd be hiding out in caves, tents, or bunkers, not resting comfortably in bed. Since believers won't be able to buy or sell without the mark, I don't think they'd be allowed to work their jobs as if nothing was going on either (grinding together - two men shall be in the field).

Just something to think about. Those are some verses that explain a possible pre-trib rapture. I really don't think anyone can know for sure exactly how it will all take place though until it actually happens.