Letter 36: 1. I know not how it was that I did not reply to your first letter; but I know that my neglect was not owing to want of esteem for you. For I take pleasure in your studies, and even in the words in which you express your thoughts; and it is my desire as well as advice that you make great attainments in your early years in the word of God, for th...

Augustine of HippoCasulanus|c. 392 AD|augustine hippo
conversioneducation booksgrief deathillnessmonasticismproperty economicstravel mobility
Theological controversy; Imperial politics; Travel & mobility

Augustine to Casulanus, greetings.

You have asked me, dearest brother, about the question that has troubled your community: on which day should the Sabbath fast be observed? This is not a trivial question, because different churches follow different practices, and the disagreement itself causes scandal among the faithful.

Let me think this through carefully with you.

Some churches fast on Saturday; others do not. Rome fasts on Saturday; Milan does not. When my mother Monica — a woman of deep piety — followed me to Milan and discovered that the church there did not fast on Saturday as she was accustomed to doing in Africa, she was troubled and uncertain about what to do. I consulted Ambrose, the bishop of Milan, and he gave me an answer I have never forgotten: "When I am in Rome, I fast on Saturday. When I am in Milan, I do not. Follow the custom of whatever church you are attending." This advice, which I also reported to my mother, she accepted as if it came from heaven.

The point is this: where Scripture does not clearly prescribe one practice over another, the custom of the local church — or the practice of the universal Church, if one can be identified — should be followed. In matters that are not settled by the clear authority of canonical Scripture, the custom of the people of God or the decrees of our predecessors must serve as law.

I could write at enormous length on this subject — and I will, because you asked. But the guiding principle is simple: do not let disagreements about fasting days become occasions for breaking communion. The devil rejoices more in a schism caused by a fast than in any feast he could inspire.

The Apostle Paul says: "The kingdom of God is not food and drink, but righteousness and peace and joy in the Holy Spirit" [Romans 14:17]. If we tear the Church apart over when to eat and when to abstain, we have missed the entire point.

As for the specific arguments: those who fast on Saturday cite various traditions and certain readings of Scripture. Those who do not fast cite others. I will walk through each argument. But my conclusion is already clear: where the practice varies and Scripture does not bind, follow the local custom in humility and preserve unity above all.

[Context: This is a lengthy letter in which Augustine addresses the controversy over Saturday fasting — a practice observed in Rome and Africa but not in Milan and parts of northern Italy. The letter is notable for preserving Ambrose's famous advice about local custom, which became a proverbial saying: "When in Rome, do as the Romans do." Augustine uses the occasion to develop a broader principle about how churches should handle matters of practice that are not explicitly settled by Scripture.]

Modern English rendering for readability. See the 19th-century translation or original Latin/Greek for scholarly use.

Related Letters