Pseudo-Chrysostom
Catena Aurea · Matthäusevangelium 7
Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven. Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? and in thy name have cast out devils? and in thy name done many wonderful works? And then will I profess unto them, I never knew you: depart from me, ye that work iniquity.
But note that He says, in my name, not in My Spirit; for they prophesy in the name of Christ, but with the spirit of the Devil; such are the diviners. But they may be known by this, that the Devil sometimes speaks falsely, the Holy Spirit never. Howbeit it is permitted to the Devil sometimes to speak the truth, that he may commend his lying by this his rare truth. Yet they cast out dæmons in the name of Christ, though they have the spirit of his enemy; or rather, they do not cast them out, but seem only to cast them out, the dæmons acting in concert with them. Also they do mighty works, that is, miracles, not such as are useful and necessary, but useless and fruitless.