If any man speak in an unknown tongue. . . . let one interpret. This verse depends on the foregoing clause, "Let all things be done to edifying." If any one sing, or teach, or speak with a tongue, let all be done to edifying, so that, e.g, if tongues are used, then let only two, or at the most three, in each assembly speak, and that in their turns, so that there may be no confusion; and let one interpret, so that the hearers may understand what is said.
Paul does not forbid speaking in tongues, however much he may belittle the gift, but he insists that it be kept under control and used for the edification of the whole church.