Ante-Nicene Fathers, Vol III:
Tertullian: Part I: Chapter XX.

Chapter XX.

How vain, then—nay, how desperate—is the reasoning of persons, who, just because they decline to lose a pleasure, hold out that we cannot point to the specific words or the very place where this abstinence is mentioned, and where the servants of God are directly forbidden to have anything to do with such assemblies! I heard lately a novel defence of himself by a certain play-lover. “The sun,” said he, “nay, God Himself, looks down from heaven on the show, and no pollution is contracted.” Yes, and the sun, too, pours down his rays into the common sewer without being defiled. As for God, would that all crimes were hid from His eye, that we might all escape judgment! But He looks on robberies too; He looks on falsehoods, adulteries, frauds, idolatries, and these same shows; and precisely on that account we will not look on them, lest the All-seeing see us. You are putting on the same level, O man, the criminal and the judge; the criminal who is a criminal because he is seen, and the Judge who is a Judge because He sees.  Are we set, then, on playing the madman outside the circus boundaries? Outside the gates of the theatre are we bent on lewdness, outside the course on arrogance, and outside the amphitheatre on cruelty, because outside the porticoes, the tiers and the curtains, too, God has eyes? Never and nowhere is that free from blame which God ever condemns; never and nowhere is it right to do what you may not do at all times and in all places.  It is the freedom of the truth from change of opinion and varying judgments which constitutes its perfection, and gives it its claims to full mastery, unchanging reverence, and faithful obedience. That which is really good or really evil cannot be ought else. But in all things the truth of God is immutable.