1 Corinthians 14:21-23

New Living Translation

²¹ It is written in the Scriptures^[a]:

²² So you see that speaking in tongues is a sign, not for believers, but for unbelievers. Prophecy, however, is for the benefit of believers, not unbelievers. ²³ Even so, if unbelievers or people who don’t understand these things come into your church meeting and hear everyone speaking in an unknown language, they will think you are crazy.