17. You might be giving thanks well enough. But the others are not being built up.
18. I thank God that I speak in other languages more than all of you do.
19. But in the church I would rather speak five words that people can understand than 10,000 words in another language. Then I would be teaching others.
20. Brothers and sisters, stop thinking like children. Be like babies as far as evil is concerned. But be grown up in your thinking.
21. In the Law it is written, "Through people who speak unfamiliar languages and through the lips of strangers I will speak to these people. But even then they will not listen to me." (Isaiah 28:11,12) That is what the Lord says.
22. So speaking in other languages is a sign for those who don't believe. It is not a sign for those who do believe. But prophecy is for believers. It is not for those who don't believe.
23. Suppose the whole church comes together and everyone speaks in other languages. And suppose visitors or unbelievers come in. Won't they say you are out of your minds?
24. But suppose unbelievers or visitors come in while everyone is prophesying. Then they will be shown by all who speak that they are sinners. They will be judged by all.
25. The secrets of their hearts will be brought out into the open. They will fall down and worship God. They will exclaim, "God is really here among you!"