1 Corinthians 15:52

in the twinkling of an eye, at the sound of the last trumpet (for the trumpet shall sound) and the dead shall be raised incorruptible, and we shall be changed:

1 Thessalonians 4:16

For the Lord himself will descend from heaven with acclamation, with the voice of the archangel, and with the trumpet of God: and the dead in Christ shall rise first;

Hebrews 12:20

(for they could not bear the strict command, if so much as a beast touch the mountain, it shall be stoned, or shot through with a dart;

Treasury of Scripture Knowledge

Summary

There shall not an hand touch it, but he shall surely be stoned, or shot through; whether it be beast or man, it shall not live: when the trumpet soundeth long, they shall come up to the mount.

Bible References

When the trumpet

1 Corinthians 15:52
in the twinkling of an eye, at the sound of the last trumpet (for the trumpet shall sound) and the dead shall be raised incorruptible, and we shall be changed:
1 Thessalonians 4:16
For the Lord himself will descend from heaven with acclamation, with the voice of the archangel, and with the trumpet of God: and the dead in Christ shall rise first;