1 Corinthians 15:51-53

Listen, I tell you a mystery: We will not all sleep, but we will all be changed — in a flash, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, the dead will be raised imperishable, and we will be changed. For the perishable must clothe itself with the imperishable, and the mortal with immortality.

Hebrews 10:25

Let us not give up meeting together, as some are in the habit of doing, but let us encourage one another — and all the more as you see the Day approaching.