1 Corinthians 14:21-23

Revised Standard Version

²¹ In the law it is written, “By men of strange tongues and by the lips of foreigners will I speak to this people, and even then they will not listen to me, says the Lord.” ²² Thus, tongues are a sign not for believers but for unbelievers, while prophecy is not for unbelievers but for believers. ²³ If, therefore, the whole church assembles and all speak in tongues, and outsiders or unbelievers enter, will they not say that you are mad?