Salvation is God forgiving our lawless deeds which brings us to a place of receiving blessings from God. Sin produces death, salvation produces joy. He then points out that blessing did not come upon Abraham when he was circumcised. It came upon him when he entered into the covenant. He received the sign of that covenant after having entered into the covenant. Paul's point is that the example of Abraham shows that he is the father of all who believe, not just of those who were circumcised. When pedobaptists say that circumcision is the precursor to baptism miss the point, it is a seal of Abraham's faith because it follows entering into the covenant and does not precede it as they do with their children.