13Therefore, one who speaks in a tongue should pray for the power to interpret. 14For if I pray in a tongue, my spirit prays but my mind is unproductive. 15What should I do then? I will pray with the spirit, but I will pray with the mind also; I will sing praise with the spirit, but I will sing praise with the mind also. 16Otherwise, if you say a blessing with the spirit, how can anyone in the position of an outsider say the “Amen” to your thanksgiving, since the outsider does not know what you are saying? 17For you may give thanks well enough, but the other person is not built up. 18I thank God that I speak in tongues more than all of you; 19nevertheless, in church I would rather speak five words with my mind, in order to instruct others also, than ten thousand words in a tongue.
20Brothers and sisters, do not be children in your thinking; rather, be infants in evil, but in thinking be adults. 21In the law it is written,
“By people of strange tongues
and by the lips of foreigners
I will speak to this people;
yet even then they will not listen to me,”
says the Lord. 22Tongues, then, are a sign not for believers but for unbelievers, while prophecy is not for unbelievers but for believers. 23If, therefore, the whole church comes together and all speak in tongues, and outsiders or unbelievers enter, will they not say that you are out of your mind? 24But if all prophesy, an unbeliever or outsider who enters is reproved by all and called to account by all. 25After the secrets of the unbeliever’s heart are disclosed, that person will bow down before God and worship him, declaring, “God is really among you.”