1 Corinthians 14:21-25

In the Law it is written: “By men of strange tongues and by the lips of strangers I will speak to this people, and even so they will not listen to Me,” says the Lord.

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

Therefore if the whole church gathers together and all the people speak in tongues, and outsiders or unbelievers enter, will they not say that you are insane?

But if all prophesy, and an unbeliever or an outsider enters, he is convicted by all, he is called to account by all;

the secrets of his heart are disclosed; and so he will fall on his face and worship God, declaring that God is certainly among you.