1 Corinthians 14:7-9

7It is the same for lifeless things that make a sound—like a flute or a harp. If they make no distinction in the tones, how will what is played be recognized?

8For if the trumpet makes an unclear sound, who will prepare himself for battle?

9So also with you with your tongue—unless you utter speech that is intelligible, how will what is spoken be understood? For you will be talking to the wind!