1 Corinthians 14:21-23

Young's Literal Translation

²¹ in the law it hath been written, that, `With other tongues and with other lips I will speak to this people, and not even so will they hear Me, saith the Lord;'

²² so that the tongues are for a sign, not to the believing, but to the unbelieving; and the prophesy [is] not for the unbelieving, but for the believing,

²³ If, therefore, the whole assembly may come together, to the same place, and all may speak with tongues, and there may come in unlearned or unbelievers, will they not say that ye are mad?