1 Corinthians 14:7-9

Revised Geneva Translation

⁷ Just as things without life give a sound, whether a pipe or a harp, how shall it be known what is piped or harped unless a distinction is made between the sounds?

⁸ And also if the trumpet gives an uncertain sound, who shall prepare himself to battle?

⁹ So likewise you, by the tongue, unless you utter words that are understood, how shall it be known what is spoken? For you shall speak into the air.