Albert Barnes on 1 Corinthians 15:52

In a moment. ενατομω. In an atom, scil. of time; a point of time which cannot be cut or divided, (a priv. and τομη from τεμνω to cut.) A single instant; immediately. It will be done instantaneously.

In the twinkling of an eye. This is an expression also denoting the least conceivable duration of time. The suddenness of the coming of the Lord Jesus is elsewhere compared to the coming of a thief in the night, 2Pet 3:10. The word rendered "twinkling," (ριπη, from ριπτω, to throw, cast,) means a throw, cast, jerk, as of a stone; and then a jerk of the eye, i.e., a wink.--Robinson.

At the last trump. When the trumpet shall sound to raise the dead. The word "last" here does not imply that any trumpet shall have been before sounded at the resurrection, but is a word denoting that this is the consummation or close of things; it will end the economy of this world; it will be connected with the last state of things.

For the trumpet shall sound. Mt 24:31.

And the dead shall be raised. Jn 5:25.

(a) "in the twinkling" 2Pet 3:10 (*) "last trump" "trumpet" (b) "trumpet" Zech 9:14, Mt 24:31 (c) "shall be raised" Jn 5:25