1 Korintus 14:22

14:22 So then, tongues are a sign not for believers but for unbelievers. Prophecy, however, is not for unbelievers but for believers.

1 Korintus 15:10

15:10 But by the grace of God I am what I am, and his grace to me has not been in vain. In fact, I worked harder than all of them – yet not I, but the grace of God with me.