Matthew Henry Commentary 1 Corinthians 14:1-5

"Follow after love; yet desire earnestly spiritual [gifts], but rather that ye may prophesy. For he that speaketh in a tongue speaketh not unto men, but unto God; for no man understandeth; but in the spirit he speaketh mysteries. But he that prophesieth speaketh unto men edification, and exhortation, and consolation. He that speaketh in a tongue edifieth himself; but he that prophesieth edifieth the church. Now I would have you all speak with tongues, but rather that ye should prophesy: and greater is he that prophesieth than he that speaketh with tongues, except he interpret, that the church may receive edifying." — 1 Corinthians 14:1-5 (ASV)

Prophesying, that is, explaining Scripture, is compared with speaking with tongues. This drew more attention than the plain interpretation of Scripture; it gratified pride more but promoted the purposes of Christian charity less; it would not do as much good for people's souls. What cannot be understood can never edify. No advantage can be reaped from the most excellent discourses if they are delivered in a language that the hearers cannot speak or understand. Every ability or possession is valuable in proportion to its usefulness. Even fervent spiritual affection must be governed by the exercise of the understanding; otherwise, they will disgrace the truths they profess to promote.