1 Corinthians 14:6–9

6 So now, brothers and sisters, if I come to you speaking in tongues, how will I benefit you unless I speak to you with a revelationb or knowledge or prophecy or teaching? 7 Even lifeless instruments that produce sounds—whether flute or harpc—if they don’t make a distinction in the notes, how will what is played on the flute or harp be recognized? 8 In fact, if the bugle makes an unclear sound, who will prepare for battle?d 9 In the same way, unless you use your tongue for intelligible speech, how will what is spoken be known? For you will be speaking into the air.