4 Bible Verses about Trumpets For Signalling

I was in the Spirit on the Lord's day, and heard behind me a loud voice as of a trumpet,

AFTER this I saw, and behold, a door was opened in heaven, and the first voice which I heard was of a trumpet speaking to me, saying, Come up hither, and I will show you things that must occur hereafter.

When, therefore, you give in charity, sound not a trumpet before you, as the hypocrites do, in the synagogues and in the streets, that they may be glorified by men. I tell you truly, they have their reward.

and the sound of a trumpet and the voice of words, which those who heard desired that the word might not be spoken to them any more,??20 for they could not bear what was commanded, And if a beast touches the mountain it shall be stoned;