16 Otherwise, if you bless with the spirit, how will he who occupies the place of the uninformed say "Amen" at your giving of thanks, since he does not understand what you say? 17 For you indeed give thanks well, but the other is not edified. 18 I thank my God I speak with tongues more than you all; 19 yet in the church I would rather speak five words with my understanding, that I may teach others also, than ten thousand words in a tongue. 20 Brethren, do not be children in understanding; however, in malice be babes, but in understanding be mature.
21 In the law it is written: "With men of other tongues and other lips I will speak to this people; And yet, for all that, they will not hear Me," says the Lord. 22 Therefore tongues are for a sign, not to those who believe but to unbelievers; but prophesying is not for unbelievers but for those who believe. 23 Therefore if the whole church comes 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 out of your mind? 24 But if all prophesy, and an unbeliever or an uninformed person comes in, he is convinced by all, he is convicted by all. 25 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.
Matthew Henry's Commentary on 1 Corinthians 14:16-25
Commentary on 1 Corinthians 14:15-25
(Read 1 Corinthians 14:15-25)
There can be no assent to prayers that are not understood. A truly Christian minister will seek much more to do spiritual good to men's souls, than to get the greatest applause to himself. This is proving himself the servant of Christ. Children are apt to be struck with novelty; but do not act like them. Christians should be like children, void of guile and malice; yet they should not be unskilful as to the word of righteousness, but only as to the arts of mischief. It is a proof that a people are forsaken of God, when he gives them up to the rule of those who teach them to worship in another language. They can never be benefitted by such teaching. Yet thus the preachers did who delivered their instructions in an unknown tongue. Would it not make Christianity ridiculous to a heathen, to hear the ministers pray or preach in a language which neither he nor the assembly understood? But if those who minister, plainly interpret Scripture, or preach the great truths and rules of the gospel, a heathen or unlearned person might become a convert to Christianity. His conscience might be touched, the secrets of his heart might be revealed to him, and so he might be brought to confess his guilt, and to own that God was present in the assembly. Scripture truth, plainly and duly taught, has a wonderful power to awaken the conscience and touch the heart.