39 I have answered those who provoked me as though I had not been provoked, for my object was to refute the Memorial, not to expose superstition. But let their very memorial make you, O Emperor, more careful. For after narrating of former princes, that the earlier of them practised the ceremonies of their fathers, and the later did not abolish them; and saying in addition that, if the religious practice of the older did not make a precedent, the connivance of the later ones did; it plainly showed what you owe, both to your faith, viz., that you should not follow the example of heathen rites, and to your affection, that you should not abolish the decrees of your brother. For if for their own side alone they have praised the connivance of those princes, who, though Christians, yet in no way abolished the heathen decrees, how much more ought you to defer to brotherly love, so that you, who ought to overlook some things even if you did not approve them in order not to detract from your brother's statutes, should now maintain what you judge to be in agreement both with your own faith, and the bond of brotherhood.
Source: Letters (New Advent)