The New Covenant Is New and the Old Covenant Is New

The idea is if the children were to be circumcised under the old covenant administration, then they should be baptized under the new. All of the previous covenants in one way or another are anticipations of what would come in the covenant of grace. And so the story of the Old Testament is a progressive unfolding of that promise that is given. The Abrahamic covenant is an element in that that looks forward to the new covenant.