Generation after generation, every male must be circumcised when he is eight days old, including those born in your household and those purchased from a foreigner—even those who are not your offspring.
12. And he that is eight days old shall be circumcised “Et filius octo dierum circumcidetur.” — “And a son of eight days shall be circumcised.” God now prescribes the eighth day for circumcision; whence it appears that this was a part of that discipline, under which he intended to keep his ancient people; for greater liberty is at this day, permitted in the administration of baptism.
Here is, I. The continuance of the covenant, intimated in three things: - 1. It is established; not to be altered nor revoked. It is fixed, it is ratified, it is made as firm as the divine power and truth can make it. 2.
Commenting on Genesis 17:7-14
And he that is eight days old shall be circumcised among you,.... A son or infant of eight days old; it might not be circumcised before, but for some reasons might be deferred longer. The reasons why this rite was ordered to be performed in infancy, according to Maimonides (d), were, because if it had been deferred to riper age it might have been neglected...