9 So also ye, unless ye utter by the tongue speech easy to understood, how shall it be known what is spoken? for ye will be speaking into the air. 10 There are, it may be, so many kinds of voices in the world, and no [kind] is without signification. 11 If then I know not the meaning of the voice, I shall be to him that speaketh a barbarian, and he that speaketh will be a barbarian unto me. 12 So also ye, since ye are zealous of spiritual [gifts], seek that ye may abound unto the edifying of the church. 13 Wherefore let him that speaketh in a tongue pray that he may interpret.
Matthew Henry's Commentary on 1 Corinthians 14:9-13
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.