1 Corinthians 14:22-25 King James Version (KJV)
22 Wherefore tongues are for a sign, not to them that believe, but to them that believe not: but prophesying serveth not for them that believe not, but for them which believe.
23 If therefore the whole church be come together into one place, and all speak with tongues, and there come in those that are unlearned, or unbelievers, will they not say that ye are mad?
24 But if all prophesy, and there come in one that believeth not, or one unlearned, he is convinced of all, he is judged of all:
25 And thus are the secrets of his heart made manifest; and so falling down on his face he will worship God, and report that God is in you of a truth.