The Rapture, as we know, will result in the world being without a single Christian. So I guess we can’t expect anyone left behind to believe in the Rapture—at least not right away. But very soon after, I think the Holy Spirit will begin (or continue) to work on some of those left behind, and will cause many to repent and wonder just what happened.
Now some may say that the Holy Spirit will leave this earth with the believers. But I really don’t think there is any Scriptural basis for that. Especially since we know that many will be save during the Tribulation. No, the Holy Spirit will be alive and well on the earthy after the Rapture, and He will be seeking out all those who will repent and be saved.
And by the way, His (the Holy Spirit’s) restraining power spoken of in 2 Thessalonians 2:6-7, is only toward the antichrist. He will restrain him from being revealed as to who he is (the antichrist) and as to the evil he wants to do. This restraining power will be in effect until the midpoint of the Tribulation.
Thus, as to the convicting power of the Holy Spirit, it will be at work from the Rapture on, and even during the Tribulation. But, like I said, from the midpoint of the Tribulation until Christ’s glorious return, the Holy Spirit will no longer restrain the antichrist—He (the Holy Spirit) will be “taken out of the way” (v. 7); thus, during that three and one-half year period He will not protect believers (or anyone) from the evil of the antichrist (except for those who are sealed, the 144,000 Jewish witnesses, Rev. 7:3-8). Nonetheless, this does not mean that the Holy Spirt will not still be at work helping people and bringing many to salvation. That is, even though He will not stop the antichrist from his evil works against Jews and Christians, He, through all the evil, will still be at work to comfort them and to convict and save all those He has chosen.
All that said, we must believe that some, perhaps many, will begin to believe in the biblical Rapture theory and to know, sadly, that they were left behind.
Now I don’t think we can know exactly how the Holy Spirit will work on people’s hearts to show them the truth of what happened, and to convict them of sin. Each case I’m sure will be different. Perhaps some will get a hold of Christian material that was left behind. Some may stumble on to an internet article, or a YouTube video, that will talk about the Rapture. Others may remember a Christian relative or friend that disappeared, and they may figure out, by the Holy Spirit’s help, that they were raptured by God.
Whatever the case may be, I think there will be some, perhaps many, who will realize the truth of what happened to all those who disappeared. Some, I suppose, will realize what happed and will still not believe—their hearts will be hardened. Many others will believe and be saved. These will be the first of the great revival (Rev. 7:9, 13-17).