Apostol § 156

Brethren, do not be children in understanding; however, in malice be ye children, but in understanding be men. In the law it is written: “With men of other tongues and other lips I will speak unto this people; and yet, for all that, they will not hear Me,” saith the Lord. Therefore tongues are for a sign, not to them that believe but to them that do not believe; but prophesying serves not for them that believe not, but for them that believe. Therefore if the whole Church come together in one place, and all speak with tongues, and there come in those who are uninformed or unbelievers, will they not say that you are mad? But if all prophesy, and an unbeliever or an uninformed person comes in, he is convinced of all, he is judged of all. And thus the secrets of his heart are revealed; and so, falling down on his face, he will worship God and report that God is truly among you.