Athanasius of Alexandria, on Ezek 9:4

“And the Lord said to him: Go through the midst of the city, through the midst of Jerusalem: and mark Thau upon the foreheads of the men that sigh, and mourn for all the abominations that are committed in the midst thereof.”

“Thus [the devil] suffers and is dishonored; and although he still ventures with shameless confidence to disguise himself, yet now, wretched spirit, he is detected rather by those who bear the sign on their foreheads; and he is even rejected by them, and is humbled and put to shame. For even if, now that he is a creeping serpent, he shall transform himself into an angel of light, yet his deception will not profit him; for we have been taught that "though an angel from heaven preach to us any other gospel than that we have received, he is anathema."”

Imported from an open dataset — not yet checked against the printed edition.