Paul puts himself into the picture. Suppose their own apostle came to Corinth and spoke only in tongues: what good would that do them? Barnes answers that it "could be of no use unless it were interpreted to them." Paul is not dismissing tongues; he says, "I would that ye all spake with tongues" (1 Corinthians 14:5). He is asking how a gift is measured in church, and his answer is: by whether it helps the hearers. Matthew Henry draws the point plainly: "Even an apostle could not edify, unless he spoke so as to be understood by his hearers."

Paul answers inside the question itself. He could profit them only by speaking "either by revelation, or by knowledge, or by prophesying, or by doctrine" (1 Corinthians 14:6), that is, in words they could take in. He then makes the same point three more ways: with pipe and harp, with the trumpet, and with foreign languages that make speaker and hearer "a barbarian" to each other (1 Corinthians 14:7-11). He closes the thought with a command: "seek that ye may excel to the edifying of the church" (1 Corinthians 14:12).

The church at Corinth was "zealous of spiritual gifts" (1 Corinthians 14:12), and speaking with tongues seems to have been highly prized there. Barnes reads the tongues in this chapter as foreign languages that the hearers did not know. The four words Paul lists are explained differently by the commentators. Barnes thinks it probable that "revelation" here means not new inspiration but making something plain, since it "stands opposed to that which is unknown and unintelligible." Gill offers more than one reading: the revelation of Jesus Christ by which Paul received the gospel he preached, or the spirit of wisdom and revelation in the knowledge of Christ, whether given at first or by a fresh revelation from heaven. Either way, all four describe speech that reaches the mind of the listener.

This question grows out of 1 Corinthians 12-13. Paul has taught that "the manifestation of the Spirit is given to every man to profit withal" (1 Corinthians 12:7), and that even "the tongues of men and of angels" without love are only "sounding brass" (1 Corinthians 13:1). So when he asks "what shall I profit you?", he is applying love to worship. God gives His gifts so that His people will be built up together, not so that one person will be admired.

Paul holds himself to the same rule he gives them. He speaks with tongues "more than ye all," yet in church he would rather speak "five words with my understanding, that by my voice I might teach others also" (1 Corinthians 14:18-19). He chooses the words that serve.