In Paul's words,
"Behold, I show you a mystery: We shall
not all sleep, but we shall all be changed 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 15:51-52

He is telling us that there is a generation of
Christians that will not experience physical
death, but will be caught up in an instant to
be with Jesus. We expect to be that generation.