But as it was easily seen to be unjust to compel freemen against their will to offer sacrifice (for even in other acts of religious service a willing mind is required), it should be counted quite absurd for one man to compel another to do honour to the gods, when he ought ever voluntarily, and in the sense of his own need, to seek their favour, lest in the liberty which is his right he should be ready to say, “I want none of Jupiter's favours; pray who are you? Let Janus meet me with angry looks, with whichever of his faces he likes; what have you to do with me?”
You have been led, no doubt, by these same evil spirits to compel us to offer sacrifice for the well-being of the emperor; and you are under a necessity of using force, just as we are under an obligation to face the dangers of it. This brings us, then, to the second ground of accusation, that we are guilty of treason against a majesty more august; for you do homage with a greater dread and an intenser reverence to Cæsar, than Olympian Jove himself. And if you knew it, upon sufficient grounds.
For is not any living man better than a dead one, whoever he be? But this is not done by you on any other ground than regard to a power whose presence you vividly realize; so that also in this you are convicted of impiety to your gods, inasmuch as you show a greater reverence to a human sovereignty than you do to them. Then, too, among you, people far more readily swear a false oath in the name of all the gods, than in the name of the single genius of Cæsar.
Source: The Apology (New Advent)