Now, brethren, if I come unto you speaking with tongues, what shall I profit you, except I shall speak to you either by revelation, or by knowledge, or by prophesying, or by doctrine?
Translate, 'But now;' seeing there is no edification without interpretation.
Revelation ... prophesying - corresponding "revelation" being the supernatural unveiling of divine truths; "prophesying," the open enunciation of such revelations. So "knowledge" corresponds to "doctrine," the gift of teaching to others our knowledge. As the former pair refers to revealed mysteries, so the latter pair to the obvious truths of salvation, brought from the common storehouse of believers.