[Moderators note: This question assumes that I Cor 15:52 refers to a special rapture of the church vs. the resurrection. For related topics on the rapture, see: https://ebible.com/questions/3953-is-the-word-rapture-in-the-bible https://ebible.com/questions/634-what-is-the-theory-of-the-rapture-of-the-church https://ebible.com/questions/4527-is-the-rapture-the-same-as-the-second-coming-of-christ]
1 Corinthians 15:52
ESV - 52 In a moment, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, and the dead will be raised imperishable, and we shall be changed.
For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
My Opinion is until they get saved, you are wasting your time.