9 So if you, in using a strange tongue, say words which have no sense, how will anyone take in what you are saying? for you will be talking to the air. 10 There are, it may be, a number of different voices in the world, and no voice is without sense. 11 But if the sense of the voice is not clear to me, I am like a man from a strange country to him who is talking, and he will be the same to me. 12 So if you are desiring the things which the Spirit gives, let your minds be turned first to the things which are for the good of the church.
Matthew Henry's Commentary on 1 Corinthians 14:9-12
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.