Was Paul being contradictory w/re to tongues in 1 Corinthians 14?

Q: Ken said...
In 1 Corinthians 14, Paul says that tongues are a sign "not for believers but for unbelievers" (v. 22), but that an unbeliever who comes to church and hears tongues will say the people in that church are out of their minds (v. 23).

Paul also says that prophecy "is for believers, not for unbelievers" (v. 22), but if an unbeliever comes to church and hears prophecy, he will "be convinced...that he is a sinner" and will "fall down and worship God" (v. 25).

Can you help me understand these conflicting statements?

A: Remember that this is a corrective message from Paul. Paul is saying that their expression of tongues when they gather is disorderly and becomes distracting to the new believer.

In 1 Corinthians 14, Paul says that tongues are a sign "not for believers but for unbelievers" (v. 22), but that an unbeliever who comes to church and hears tongues will say the people in that church are out of their minds (v. 23).

This (and the previous verse which references Isaiah 28:11) is a reminder that those who hear things they do not understand are under judgment – and though the Corinthians themselves are operating within what is a genuine gift which might edify them personally, when they do so collectively, they are not edifying one another and they are certainly not edifying the non-believer. Used in such a way, it is like the tongue of the Babylonians – foreign to those who were taken into captivity.

Paul also says that prophecy "is for believers, not for unbelievers" (v. 22), but if an unbeliever comes to church and hears prophecy, he will "be convinced...that he is a sinner" and will "fall down and worship God" (v. 25).

The church is built up by the gift of prophecy (forth-speaking), which includes, by the way, the proclamation of the word in confrontation. So, while prophecy is given to the church for the building up of the saints in the Word, it can also bring conviction to the non-believer who hears and is convicted.