Charles Ellicott Commentary 1 Corinthians 15:52

"in a moment, in the twinkling of an eye, at the last trump: for the trumpet shall sound, and the dead shall be raised incorruptible, and we shall be changed." — 1 Corinthians 15:52 (ASV)

The last trump.—The trumpet was used to summon an assembly (Exodus 20:18; Psalms 81:3; Isaiah 18:3; Isaiah 27:13) or to sound a warning. The last trumpet is the one which concludes a series which has already been sounding at intervals in notes of warning to the nations (Psalms 47:5; Isaiah 27:13; Jeremiah 51:27). This verse states with reiterated emphasis that this change shall not be a protracted process, but a sudden and momentary alteration in the condition of our bodies.