Charles Ellicott Commentary 1 Corinthians 14:4

"He that speaketh in a tongue edifieth himself; but he that prophesieth edifieth the church." — 1 Corinthians 14:4 (ASV)

He who speaks in an unknown tongue.—Better, He who speaks in a tongue. The introduction of the word “unknown” destroys the whole force of the passage. All tongues—as distinct from languages—were unknown, i.e., unintelligible. The gift of prophecy is superior in usefulness to that of tongues, and therefore to be preferred. The use of the word “edify,” as applied to an individual solely, as distinct from the individual as a part of the whole Church, is unusual with St. Paul (see Note on 1 Corinthians 8:1), but is introduced so as to make the antithesis verbally as well as logically more striking.