7 Let, then, that invidious complaint of the Roman people come to an end. Rome has given no such charge. She speaks with other words. “Why do you daily stain me with the useless blood of the harmless herd? Trophies of victory depend not on the entrails of the flocks, but on the strength of those who fight. I subdued the world by a different discipline. Camillus was my soldier, who slew those who had taken the Tarpeian rock, and brought back the standards taken from the Capitol; valour laid those low whom religion had not driven off.
What shall I say of Attilius [Regulus], who gave the service of his death? Africanus found his triumphs not among the altars of the Capitol, but among the lines of Hannibal. Why do you bring forward the rites of our ancestors? I hate the rites of Neros. Why should I speak of the Emperors of two months, and the ends of rulers closely joined to their commencements. Or is it perchance a new thing for the barbarians to cross their boundaries? Were they, too, Christians in whose wretched and unprecedented cases, the one, a captive Emperor, and, under the other, the captive world made manifest that their rites which promised victory were false.
Was there then no Altar of Victory? I mourn over my downfall, my old age is tinged with that shameful bloodshed. I do not blush to be converted with the whole world in my old age. It is undoubtedly true that no age is too late to learn. Let that old age blush which cannot amend itself. Not the old age of years is worthy of praise but that of character. There is no shame in passing to better things. This alone was common to me with the barbarians, that of old I knew not God. Your sacrifice is a rite of being sprinkled with the blood of beasts.
Why do you seek the voice of God in dead animals? Come and learn on earth the heavenly warfare; we live here, but our warfare is there. Let God Himself, Who made me, teach me the mystery of heaven, not man, who knew not himself. Whom rather than God should I believe concerning God? How can I believe you, who confess that you know not what you worship?”
Source: Letters (New Advent)