1 Corinthians 14:22 in the King James Version
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.
Context
21 In the law it is written, “By men of strange languages and by the lips of strangers I will speak to this people. They won’t even listen to me that way, says the Lord.”
22 Therefore other languages are for a sign, not to those who believe, but to the unbelieving; but prophesying is for a sign, not to the unbelieving, but to those who believe.
23 If therefore the whole assembly is assembled together and all speak with other languages, and unlearned or unbelieving people come in, won’t they say that you are crazy?