What does the person who prophesies do for the congregation?

According to Scripture, the person who prophesies speaks God's word to men for edification, exhortation, and comfort. He lifts up, supports, and enlarges the congregation, enhancing and helping all who hear him. Unlike tongues that edify self, prophecy edifies the whole congregation.

Les explains that prophecy is the flip side of the tongues issue. The one who prophesies, or speaks forth the word as a gifted individual, speaks unto men to edification. Les says edification means to lift them up, to support them, to enlarge them. So these men who had the gift of speaking the word of God were enhancing the congregation and helping all that heard them. They also exhort and comfort. In verse 4, Paul contrasts this with tongues, which edifies the speaker himself, whereas the one who prophesies edifies the whole congregation. Les emphasizes that this is not an ego trip but a ministry that builds up the hearers.

1 Corinthians 14:3

But he that prophesieth speaketh unto men to edification, and exhortation, and comfort.

What did the men with the gift of speaking the word of God do for the congregation?

They enhanced the congregation, helping all who heard them by exhorting and comforting them. Their speaking forth God's word brought edification, lifting up, supporting, and enlarging the hearers. They edified the whole congregation, not merely themselves. This helped the congregation.