1 Corinthians 14:22-25
14:22 So then, tongues are a sign not for believers but for unbelievers. Prophecy, however, is not for unbelievers but for believers.
14:23 So if the whole church comes together and all speak in tongues, and unbelievers or uninformed people enter, will they not say that you have lost your minds?
14:24 But if all prophesy, and an unbeliever or uninformed person enters, he will be convicted by all, he will be called to account by all.
14:25 The secrets of his heart are disclosed, and in this way he will fall down with his face to the ground and worship God, declaring, “God is really among you.”