1 Corinthians 14:29 - Ellicott's Commentary On The Whole Bible

Let the prophets speak. — Here follows the application, to those who had the gift of prophecy, of the general principle, Let all be done to edification. Only two or three prophets are to speak in each assembly on each occasion; the others (not “other,” as in English version) who had the gift are to sit by silent and judging, i.e., determining whether the utterances were from the Spirit of God. (See 1 Corinthians 12:3, and 1 John 4:1-3.) If, however, while one prophet was standing speaking there came a sudden revelation of truth to some other prophet who was sitting by, the speaker would pause, and the other prophet give utterance to the inspiration which had come to him. The suddenness of the revelation would show that it was a truth needed there and then, and so should find utterance without delay.