Several collections of monastic legislation are known in Syriac: East and West Syrian rules, written in the Eastern Roman or Persian environment. These normative texts are what remains of a larger body of writings that has in large part been lost, and which must be considered in its context of production as a whole, albeit a heterogeneous one. Certain pieces of monastic legislation were written down after a long period of ascetic experience: this process of composition arose from the need to codify and readjust both individual and community actions. By examining the example of the rule of Abraham of Kaškar, written in 571 at the Great Monastery on Mount Izla, Northern Mesopotamia, we show how a “community laboratory” came to formulate these prohibitions and apply a penal practice aimed at protecting daily life within the community. We also show how the rule was first of all a means of preserving a Christological identity.