Moses therefore gave unto you circumcision - Moses commanded you to circumcise your children, Leviticus 12:3. The word “therefore” in this place - literally “on account of this” - means, “Moses on this account gave you circumcision, not because it is of Moses, but of the fathers;” that is, the reason was not that he himself appointed it as a new institution, but he found it already in existence, and incorporated it in his institutions and laws.
Not because ... - Not that it is of Moses. Though Jesus spoke in accordance with the custom of the Jews, who ascribed the appointment of circumcision to Moses, yet he is careful to remind them that it was in observance long before Moses. So, also, the Sabbath was kept before Moses, and alike in the one case and the other they ought to keep in mind the design of the appointment.
Of the fathers - Of the patriarchs, Abraham, Isaac, and Jacob, Genesis 17:10.
Ye on the sabbath-day ... - The law required that the child should be circumcised on the eighth day. If that day happened to be the Sabbath, yet they held that he was to be circumcised, as there was a positive law to that effect; and as this was commanded, they did not consider it a breach of the Sabbath.
A man - Not an adult man, but a man-child. See John 16:21; “She remembereth no more the anguish, for joy that a man is born into the world.”