19 The slaughter of multitudes would not seem strange to the Pagan, unless he denied the judgment of God, which Pagans do not; for they allow that all things in the universe, from the highest to the lowest, are governed by God's providence. But if he would not allow this, he would be convinced either by the authority of Pagan writers, or by the more tedious method of demonstration; and if still obstinate and perverse, he would be left to the judgment which he denies.
Then, if he were to give instances of the destruction of men for no offense, or for a very slight one, we should show that these were offenses, and that they were not slight. For instance, to take the case already referred to of the wedding garment, we should prove that it was a great crime in a man to attend the sacred feast, seeking not the bridegroom's glory, but his own, or whatever the garment may be found on better interpretation to signify. And in the case of the slaughter before the king of those who would not have him to reign over them, we might perhaps easily prove that, though it may be no sin in a man to refuse to obey his fellow-man, it is both a fault and a great one to reject the reign of Him in whose reign alone is there righteousness, and happiness, and continuance.
Source: Reply to Faustus the Manichaean (New Advent)