בראשית, פרק י״ז, פסוק י״ב

The Commandment of circumcision is established with a precise timeframe and a broad scope that extends far beyond biological descendants. The requirement to perform the act at exactly eight days of age serves specific practical and legal purposes. Specifying days ensures the procedure takes place during daylight hours rather than at night, and it prevents any misunderstanding that the waiting period might be eight years [תורה תמימה]. Interestingly, waiting eight days after a child's birth was already a recognized practice in the ancient world among various nations as the appropriate time for naming a child [אם למקרא]. Because an eight-day-old infant lacks the awareness to fulfill the Commandment himself, the practical responsibility to bring him into the covenant rests entirely upon his father or the rabbinic court [אבן עזרא, רד״ק, מלבי״ם, ביאור יש״ר, מחוקקי יהודה].

While the directive applies across generations to the nation of Israel [רד״ק], it immediately expands to include dependents within the household. This encompasses those born in the house and those purchased with money. The primary approach among commentators is that those born in the house refer to the children of slaves or maidservants born within the estate, whereas those bought with money are slaves acquired after their birth. However, other perspectives broaden the first category to include Abraham's own biological sons and grandsons [שד״ל, ביאור שטיינזלץ], or specifically the son of a maidservant who has converted [ר' סעדיה גאון].

The requirement to circumcise foreign slaves raises a fundamental question about their spiritual status and whether they truly enter the covenant. Commentators draw a clear distinction between the circumcision of sons and that of slaves. Sons undergo the act to enter an eternal covenant with God. Slaves, on the other hand, are circumcised by virtue of being the master's property, conceptually similar to the requirement that a person's animals must rest on the Sabbath [מלבי״ם]. Nevertheless, the act fundamentally alters the slaves' status, elevating them from being complete foreigners and partially integrating them into the community of Israel [ברכת אשר על התורה].

The timing for a slave's circumcision depends on how he entered the household. If he is born in the master's possession, such as when a master purchases a pregnant maidservant, he is treated like an Israelite and circumcised on the eighth day. Conversely, if a slave is purchased after he is already eight days old, or if an adult slave converts, he is circumcised immediately on the day of his acquisition or conversion [רד״ק, תורה תמימה, ר' סעדיה גאון].

Although the instruction is established for all future generations, it is later repeated as a direct, personal order to Abraham. This repetition ensures clarity, preventing the assumption that the obligation only applies to infants born from that point forward. Instead, it mandates the circumcision of everyone already present in Abraham's household at that exact moment, regardless of their age [אבן עזרא, מחוקקי יהודה]. Because there were no eight-day-old infants in his home at the time, all the men of Abraham's household underwent the procedure together on that very day [רד״ק].