The Sages received an oral tradition that the mitzva of circumcision overrides when it is performed at its proper time, on the eighth day after birth. Although all the Sages accepted this tradition, they disputed many details of its application. Such details include the handling of borderline cases, the precise definitions of the act of circumcision, and the actions necessary for its performance.
Several issues arise with regard to circumcision on. The first question pertains to situations in which it is not entirely clear whether there is a mitzva to circumcise the child or whether the proper time for circumcision has arrived. Some Sages are of the opinion that circumcision overrides only if there is absolutely no doubt as to its obligation. Others hold that in some circumstances an uncertain obligation to circumcise does override, and these Sages debate which conditions are required.
Another issue is whether the preparations for circumcision override. The medical attention the baby will require immediately after the circumcision does override, as his life could be endangered if he does not receive it. The Sages consider whether actions to prepare for the circumcision, such as bringing the knife and preparing it for use, also override, and if so, which preparations are considered essential in this regard.
Another essential issue pertains to how broadly circumcision overrides. Does circumcision override at every stage of the operation no matter how it is performed, and is anyone involved in circumcision exempt from prohibitions? Or perhaps circumcision overrides only when one completes the mitzva properly and in its entirety? To address these questions it becomes necessary to clarify the scope of the mitzva and to identify its obligatory components.