Moses gave you the law about circumcision. (But really Moses did not give you circumcision; it came from our ancestors.) And yet you circumcise a baby boy on a Sabbath day.
God made an agreement with Abraham, the sign of which was circumcision. And so when Abraham had his son Isaac, Abraham circumcised him when he was eight days old. Isaac also circumcised his son Jacob, and Jacob did the same for his sons, the twelve ancestors of our people.
This is what I mean: God had an agreement with Abraham and promised to keep it. The law, which came four hundred thirty years later, cannot change that agreement and so destroy God’s promise to Abraham.