A.T. Robertson 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)

In a moment (εν ατομω). Old word, from α privative and τεμνω, to cut, indivisible: Scientific word for atom which was considered indivisible, but that was before the day of electrons and protons. Only here in N.T.

In the twinkling of an eye (εν ριπη οφθαλμου). Old word ριπη from ριπτω, to throw. Only here in N.T. Used by the Greeks for the flapping of a wing, the buzz of a gnat, the quivering of a harp, the twinkling of a star.

At the last trump (εν τη εσχατη σαλπιγγ). Symbolical, of course. See on 1 Thessalonians 4:16; Matthew 24:31.