Bible: 1 Cor 14:20-22
14:20 Brothers and sisters, 1 do not be children in your thinking. Instead, be infants in evil, but in your thinking be mature. 14:21 It is written in the law: “By people with strange tongues and by the lips of strangers I will speak to this people, yet not even in this way will they listen to me,” 2 says the Lord. 14:22 So then, tongues are a sign not for believers but for unbelievers. Prophecy, however, is not for unbelievers but for believers.