I think the question is built on a false, if widely held, premise. The covenant theology of the 16th century was formed from threads that existed in the patristic and medieval periods. The Fathers taught various aspects of covenant theology. They used the covenant of grace to unify the history of redemption in just the way that the Reformed did in the 16th century as they defended infant baptism on the basis of the one covenant of grace made with Abraham and changed only in administration -- not in substance. Bullinger wrote his treatise in the early 1530s on this very basis but much of what he said was anticipated by Irenaeus and others in the patristic period.

rsc

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R. Scott Clark, D.Phil
Professor of Church History and Historical Theology

"For Christ, His Gospel, and His Church"
Associate Pastor
Oceanside URC
The Heidelblog