1 Corinthians 14:20-22

20Brothers and sisters, stop thinking like children. In regard to evil be infants, but in your thinking be adults. 21In the Law it is written: “With other tongues and through the lips of foreigners I will speak to this people, but even then they will not listen to me, says the Lord.” 22Tongues, then, are a sign, not for believers but for unbelievers; prophecy, however, is not for unbelievers but for believers.