“The Lord himself shall descend from heaven, with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first; then we that are alive, that are left, shall together with them be caught up in the clouds, to meet the Lord in the air.”ASV
What it establishes
That there is a catching-up at all, that the dead in Christ precede the living, that it is loud and public rather than secret in the sense of silent, and that Paul gives it as comfort to grieving people.
What it leaves open
It does not say when, relative to any tribulation. Paul's pastoral question is who goes first, not what year it is.
