1 Corinthians 14:2-4

For he that speaketh in an unknown tongue speaketh not unto men, but unto God: for no man understandeth him; howbeit in the spirit he speaketh mysteries. But he that prophesieth speaketh unto men to edification, and exhortation, and comfort. He that speaketh in an unknown tongue edifieth himself; but he that prophesieth edifieth the church.