1 Corinthians 14:6-8

Brothers and sisters, will it help you if I come to you speaking in different languages? No! It will help you only if I bring you a new truth or some new knowledge, or prophecy, or teaching. It is the same as with lifeless things that make sounds—like a flute or a harp. If they do not make clear musical notes, you will not know what is being played. And in a war, if the trumpet does not give a clear sound, who will prepare for battle?