1 Corinthians 14:6

Now, brethren. — Transferring these things to himself in an image the Apostle reinforces the preceding teaching. Now (i.e., seeing that these things are so), what profit would I be to come to you speaking in tongues? I have been telling you that you cannot profit others: I ask you, do you think I speaking in tongues could profit you?

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