There is an analogy between circumcision and baptism, but it is wrong and unbiblical to make them identical.
The New Testament teaches that circumcision was replaced by circumcision of the heart. We do not believe that the NT teaches that circumcision was replaced by baptism, but rather it was replaced by spiritual circumcision – the circumcision of the heart (e.g. Rom 2:28-29; Col 2:11-12, see this too).
The Nature of the Old Covenant
Johnson identifies “continuity” to be the essence of Westminster Covenant Theology. It is the pin holding it all together. The emphasis in Westminster Covenant Theology is upon continuity between the covenants. In Dispensationalism it is upon the discontinuity. The 1689 Baptist position seeks a balanced position between both continuity and discontinuity.
The majority of Reformed Paedobaptists believe that the Mosaic Covenant was an administration of the Covenant of Grace and thus it was a covenant of grace, rather than of works.
Johnson begs to differ along with 1689 Federalists and even some Paedobaptists. A lot of assumptions and inferences are drawn by Paedobaptists concerning the New Covenant based upon the Mosaic being an administration of the Covenant of Grace which would be unjustified if it were not a covenant of grace. One thinks of the mixed membership of the covenant. Rom 9:6 says “…For not all who are descended from Israel belong to Israel,” therefore our Westminster brethren assume that this continues also in the New Covenant. All who were descended from Israel were in the covenant, or as they would say in the outward administration and received the sign of the Abrahamic Covenant. All who belonged to the covenant participated in the essence and inner administration and truly knew God.
Johnson goes on to prove that the Mosaic Covenant was not an administration of the Covenant of Grace, but rather was a covenant of works. He demonstrates this by showing its conditionality, curses, the fact that it was broken and also by going to the analogy of Paul in Galatians 4:21-31. Galatian...