But not 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 daemons 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 daemons acting in concert with them. Also they do mighty works, that is, miracles, not such as are useful and necessary, but useless and fruitless.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).