9 So with yourselves; if in a tongue you utter speech that is not intelligible, how will anyone know what is being said? For you will be speaking into the air. 10 There are doubtless many different kinds of sounds in the world, and nothing is without sound. 11 If then I do not know the meaning of a sound, I will be a foreigner to the speaker and the speaker a foreigner to me. 12 So with yourselves; since you are eager for spiritual gifts, strive to excel in them for building up the church. 13 Therefore, one who speaks in a tongue should pray for the power to interpret. 14 For if I pray in a tongue, my spirit prays but my mind is unproductive.
15 What 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. 16 Otherwise, 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? 17 For you may give thanks well enough, but the other person is not built up. 18 I thank God that I speak in tongues more than all of you; 19 nevertheless, in church I would rather speak five words with my mind, in order to instruct others also, than ten thousand words in a tongue.
Matthew Henry's Commentary on 1 Corinthians 14:9-19
Commentary on 1 Corinthians 14:6-14
(Read 1 Corinthians 14:6-14)
Even an apostle could not edify, unless he spoke so as to be understood by his hearers. To speak words that have no meaning to those who hear them, is but speaking into the air. That cannot answer the end of speaking, which has no meaning; in this case, speaker and hearers are barbarians to each other. All religious services should be so performed in Christian assemblies, that all may join in, and profit by them. Language plain and easy to be understood, is the most proper for public worship, and other religious exercises. Every true follower of Christ will rather desire to do good to others, than to get a name for learning or fine speaking.
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.