Many post trib rapture proponents will object to the pretrib position because of the “last trumpet” comment Paul made in 1 Corinthians 15:52 and the “first Resurrection” comment made in Revelation 20:6. However under closer examination neither does much to prove a post trib rapture.
“The last trump”
In 1 Corinthians Paul has a theme of explaining how feasts of the Old Testament relate to what he is explaining. In 1 Cor 5:6-8 he talks about the feast of Passover and unleavened bread and explains how that relates to Jesus death. In 1 Cor 15:20-22 he shows how the feast of firstfruits relates to to the Resurrection. A few verses later he mentions the “the last trump” referring to the feast of Trumpets. During the feast of Trumpets “the last trump” called “Tekiah Godolah” represented the hope of redemption. So it makes perfect sense to equate this hope of redemption to the rapture of the church. Chronologically it will be the “last” trump regarding the church- which is his audience- but again it was a reference to the feast of Trumpets and the Tekiah Godolah, the hope of redemption. There is no reason to believe that a trumpet involved with judgements happening during the tribulation is the same as a trumpet that involves the hope of the rapture. Clearly the rapture, when it happens, will fulfill the feast of trumpets.
The First Resurrection
This argument is basically that because Revelation 20 says “first Resurrection” there is no other resurrections prior to this. This is just obviously not what the Text intends. Is Jesus Resurrected? Yes. Some Old Testament saints were resurrected in Matthew 27:52. The 2 witnesses of Revelation 11:11-12 were Resurrected. So clearly the “first Resurrection” spoken of in Rev 20:5 is not saying that no one is Resurrected before hand. It is contrasting the Resurrection before the 1000 year reign of Christ on earth with the one after that. So in context all those Resurrected before the 1000 year reign (Millennial reign) would be included in the “first Resurrection” contextually. So this argument is really refuted before it is spoken by someone who already believes Jesus is Resurrected and doesn’t equate to much of an argument at all.