Paul calls circumcision a “seal of righteousness” in Romans 4:11, and that same phrase has historically been applied to baptism.
But what does it mean to be a “seal of righteousness”? A seal (Greek sphragis) is an identifying mark. The word is used to describe brands on animals, identifying tattoos on slaves, signs that identify a man’s regiment in the military. To be sealed is to be identified in some way.
A “seal of righteousness,” it would seem, is a mark that identified the one sealed as “righteous.” That’s true for Abraham: He trusted Yahweh’s promise, Yahweh counted it for righteousness and thus considered Abraham to be righteous, and the seal of circumcision imposed that status on Abraham’s flesh. Abraham would have explained his circumcision as a seal that Yahweh considered him righteous.
But then that same seal is applied to the infant Isaac, and then many other infants, on the eighth day. It’s still a “seal of righteousness.” Changing Isaac’s nappies, Sarah could have seen Isaac’s circumcision and thought, “Yahweh sealed my little son as a righteous one! Praise to Yahweh!”
When we apply this logic to baptism, as paedobaptists are wont to do, what are we to conclude? Is baptism a “seal of righteousness,” also for our children?