Jamieson, Fausset and Brown on 1 Corinthians 14:24

24. all--one by one (1Co 14:31).

prophesy--speak the truth by the Spirit intelligibly, and not in unintelligible tongues.

one--"anyone." Here singular; implying that this effect, namely, conviction by all, would be produced on anyone, who might happen to enter. In 1Co 14:23 the plural is used; "unlearned or unbelievers"; implying that however many there might be, not one would profit by the tongues; yea, their being many would confirm them in rejecting the sign, as many unbelieving men together strengthen one another in unbelief; individuals are more easily won [Bengel].

convinced--convicted in conscience; said of the "one that believeth not" (Joh 16:8, 9).

judged--His secret character is opened out. "Is searched into" [Alford]. Said of the "one unlearned" (compare 1Co 2:15).