Jeremias 13

Jeremias 13:23

For as the prophet speaks," If the Ethiopian changes his skin, or the leopard his spots," then will they be willing to think religiously who have been instructed in irreligion. You, however, beloved, on receiving this, read it by yourself. If you approve of it, read it also to the brethren who happen to be present, that they, too, on hearing it, may welcome the council's zeal for the truth and the exactness of its sense and may condemn that of Christ's foes, the Arians, and the futile pretenses, which for the sake of their irreligious heresy they have been at the pains to frame among themselves. — DEFENSE OF THE NICENE DEFINITION 7:32