Charles Ellicott Commentary 1 Corinthians 14:6

"But now, brethren, if I come unto you speaking with tongues, what shall I profit you, unless I speak to you either by way of revelation, or of knowledge, or of prophesying, or of teaching?" — 1 Corinthians 14:6 (ASV)

Now, brothers and sisters.—By applying these things to himself as an illustration, the Apostle reinforces the preceding teaching. Now (that is, seeing that these things are so), of what profit would I be to you, if I came speaking in tongues? I have been telling you that you cannot profit others: I ask you, do you think I, by speaking in tongues, could profit you?

Except I shall speak to you either . . .—This is an expansion of the “interpretation of tongues” from the previous verse, and which is the condition on which any usefulness of the gift depends. The “revelation” and the “knowledge” are the internal gifts in the teacher himself which are the sources of his power to communicate “prophecy” (that is, general exhortation), or “doctrine” (that is, systematic religious instruction) to his hearers.