There is great confusion about when the time of the rapture of the Church to heaven relative to the coming Tribulation—before, during or after it. This confusion is propagated by the determination of many to base doctrine for the rapture upon false doctrine concerning both the Church and the Tribulation.
It will be my contention that this confusion will not be sorted out except by recognizing that the Church Age is one of the dispensations of God. Even dispensationalists, those who accept that God has dealt with and will continue to deal with man through different dispensations, need to recognize some vital differences between the Church Age and other dispensations.
Paul called this Church Age “the dispensation of the grace of God”. And this is surely because in this dispensation, as in no other dispensation, salvation is by the grace of God without works. Also believers in this dispensation, as in no other, are to live by grace not law. These distinctions (ignored by most) are sufficient to establish that the Rapture of the Church will be outside of (before) the Tribulation.
Also the dispensation of the Church Age, including its rapture, is said by Paul to be a mystery unknown to all until it was revealed to him. That means all references to a rapture before Paul wrote his epistles must refer to a rapture other than the rapture of the Church. Such references (and there are several) lead us to discern another rapture, its nature, and its time.
See slides The Two Raptures for a reorganized discussion of these things.