(3) And in the eighth day.—When the seven days had passed by during which the mother remained un clean, the boy is to be circumcised, since on the eighth day the first period of her extreme state of impurity ceases, and she no more imparts defilement to whomsoever or to whatsoever she touches. For the rite of circumcision, see Genesis 17:10; Genesis 17:13.

12:1-8 Ceremonial purification. - After the laws concerning clean and unclean food, come the laws concerning clean and unclean persons. Man imparts his depraved nature to his offspring, so that, excepting as the atonement of Christ and the sanctification of the Spirit prevent, the original blessing, Increase and multiply, Ge 1:28, is become to the fallen race a direful curse, and communicates sin and misery. Let those women who have received mercy from God in child-bearing, with all thankfulness own God's goodness to them; and this shall please the Lord better than sacrifices.On circumcision, see Genesis 17:5 note. 2. If a woman, &c.—The mother of a boy was ceremonially unclean for a week, at the end of which the child was circumcised (Ge 17:12; Ro 4:11-13); the mother of a girl for two weeks (Le 12:5)—a stigma on the sex (1Ti 2:14, 15) for sin, which was removed by Christ; everyone who came near her during that time contracted a similar defilement. After these periods, visitors might approach her though she was still excluded from the public ordinances of religion [Le 12:4]. Which law is here repeated, because the woman’s uncleanness lasting for seven days, was one, though not the only, reason why the child’s circumcision was put off till the eighth day.

And in the eighth day the flesh of his foreskin shall be circumcised. Or the foreskin of his flesh, that is, of the man child born according to the law, Genesis 17:12 and this seems to furnish out a reason why a male child was not circumcised before the eighth day, and why it was then, because before that its mother was in her separation and uncleanness, and then was freed from it; and so the Targum of Jonathan. The circumcision of a male child on the eighth day was religiously observed, and even was not omitted on account of the sabbath, when the eighth day happened to be on that; see Gill on John 7:22, John 7:23. It is an observation of Aben Ezra on this place, that the wise men say "in the day", and not in the night, lo, he that is born half an hour before the setting of the sun is circumcised after six days and a half, for the day of the law is not from time to time. And in the eighth day the flesh of his foreskin shall be circumcised.