1 Corinthians 14:7-9

Amplified Bible, Classic Edition

⁷ If even inanimate musical instruments, such as the flute or the harp, do not give distinct notes, how will anyone [listening] know or understand what is played?

⁸ And if the war bugle gives an uncertain (indistinct) call, who will prepare for battle?

⁹ Just so it is with you; if you in the [unknown] tongue speak words that are not intelligible, how will anyone understand what you are saying? For you will be talking into empty space!