I think I know what you're alluding to, but if I'm mistaken, by all means set me straight.
In 1 Thess 4.13-18, Paul is writing of both the 'raising to life' of the dead in Christ and of what has been all too commonly thought of as 'the Rapture' (dum dum dum-dum). But the phrase you're referring to, hoi nekroi en Christo anastesontai proton, in verse 16, definitely has to do with the dead in Christ being raised to new life. After all, directly translated it says: "the dead in Christ will rise first." It's hard to get more clear than that. However, in verse 17, where Paul mentions how those who are in Christ and alive at his coming, "together with them (the previously dead that Christ will bring with him) will be caught up (harpazein; or 'snatched', since the nuance it carries is of a rather violent grasping) in the clouds to a meeting with the Lord in the air," while the verb harpazein is often used in conjunction with the idea of death in ancient literature (Lucian paints the picture of a bereaved father utilising conventional language as he cries out to his dead son: "Dearest child, you are gone from me, dead, snatched away before your time, leaving me alone and wretched" [Funerals 13]), it appears that the Jewish apocalyptic writers of the period used this term to refer to those people who will still be alive at the coming of the Day of the Lord. For example, in 4 Ezra we find, "It will be that whoever remains after all that I have foretold to you will be saved and will see my salvation and the end of my world. And they will see the men who were snatched up, who from their birth have not tasted death; and the heart of the earth's inhabitants will be changed and converted to a different spirit" (6.25-26), as well as, "Lay up in your heart the signs that I have shown you, the dreams that you have seen, and the interpretations that you have heard; for you will be snatched up from among men, and henceforth you will live with my son and with those like you, until the times are ended" (14.8-9). Nevertheless, we should not be thinking of this in terms of believers literally rising off the ground and floating up to see Jesus descending till we all meet somewhere at cloud level. Paul is employing symbolic imagery where we do damage to the text if we take it too literally. For instance, the Greek word translated as "a meeting" in the Thessalonian passage, apantesis, bore a technical meaning in the Greco-Roman world in relation to the visits of the emperor or other dignitaries to a given city, where the visitor would be formally met by the citizens, or a deputation of them, who had gone out from the city for this purpose, to ceremonially escort them back into the city. Thus Paul is here pointing to how Christ is the true emperor whose return should be officially recognized by us with no less importance and pomp than would be if an earthly emperor were arriving. Except in this case, rather than merely an imperial visit, Paul informs us that Christ's return will be permanent, for kai houtos pantote sun kurio esometha, "and so (in this manner) we will always be with the Lord" (1 Thess 4.17c).