What does 1 Corinthians 14:5 mean?
Scripture describes how the gift of prophecy is more helpful to the church than the gift of tongues. Paul has written that the one who prays in an unknown language to God, by the power of the Holy Spirit, is "built up." Likely, this deepened the faith of those who were given this gift.The problem was that, when exercised at gatherings of the church, speaking in languages unknown to others did not build others up—they could not understand what was being said. Paul does not discourage any of the Christians in Corinth from praying in tongues to the Lord if given that gift. In fact, Paul's desire is that everyone would have this gift. He describes it as an enormously positive thing for those individuals.
For the church, however, when gathered together, the gift of prophecy was even more desirable. It allowed the gifted one to serve everybody in the room, not just God and himself.
Paul has previous written that all the gifts are needed by the church, the body of Christ. Now, he says that the one who prophesies is greater than the person who speaks in an unknown language in prayer. The only exception would be if someone with the gift of interpretation were present and able to interpret what the tongues-speaker was saying for the benefit of all.
In ranking prophecy over uninterpreted tongues, Paul is revealing again the purpose of the spiritual gifts: building up the church.