1 Corinthians 14:21-23

Darby Translation

²¹ It is written in the law, By people of other tongues, and by strange lips, will I speak to this people; and neither thus will they hear me, saith the Lord.

²² So that tongues are for a sign, not to those who believe, but to unbelievers; but prophecy, not to unbelievers, but to those who believe.

²³ If therefore the whole assembly come together in one place, and all speak with tongues, and simple [persons] enter in, or unbelievers, will not they say ye are mad?