I Coríntios 14:22

22 Tongues, then, are a sign, not for believers but for unbelievers; prophecy, however, is not for unbelievers but for believers.

22 Wherefore tongues are for a sign, not to them that believe, but to the unbelieving: but prophesying [is for a sign], not to the unbelieving, but to them that believe.