He that speaketh in an unknown tongue edifieth himself; but he that prophesieth edifieth the church. He that speaketh in an unknown tongue - In the Hebrew for instance, the knowledge of the depth and power of which he has got by a Divine revelation, edifieth himself by that knowledge.
But he that prophesieth - Has the gift of preaching.
Edifieth the Church - Speaketh unto men to edification, exhortation, and comfort, 1 Corinthians 14:3.