'Sound' in the Bible

For if the trumpet gave an uncertain sound, who would prepare himself for war?

If then I don't know the meaning of the sound, I would be to him who speaks a foreigner, and he who speaks would be a foreigner to me.

in a moment, in the twinkling of an eye, at the last trumpet. For the trumpet will sound, and the dead will be raised incorruptible, and we will be changed.