This overview is sufficient to show how the older writings can manifest the covenant doctrine in Reformed theology. But, one might perhaps say, that only applies to the covenant of grace. These historical data cannot prove that the covenant of works belonged to the old Reformed school. This contention has been expressed repeatedly. In the second half of the seventeenth century Vlak and Bekker declared themselves against the covenant of works on the grounds that it was an invention of the theologians of that period and was not encountered in the older Reformed theologians. It was supposed that Lubbertus, Makkowski, and Cloppenburg were the first to have introduced it. Just as Cocceius has occasionally been looked upon as the discoverer of the covenant concept in general, so also some wanted to maintain that the doctrine of the covenant of works had been thought up in the period immediately preceding Cocceius. If this is taken to mean that previously this doctrine had not been worked out in every detail and was not presented in all clarity as was the case later, then there is some truth to it.
But whoever has the historical sense to be able to separate the mature development of a thought from its original sprouting and does not insist that a doctrine be mature at birth, will have no difficulty in recognizing the covenant of works as an old Reformed doctrine. Already with Ursinus in the Larger Catechism the question: “What does the divine law teach you?” is answered:“What kind of a covenant God entered into with man at the creation and how man behaved in the keeping of that covenant,” etc. Likewise, Olevianus speaks of the covenant of law, the covenant of nature, the covenant of creation in contradistinction to the covenant of grace. Sometimes, it is true, he means by it the promulgation of the Mosaic law, but in other places it is no less clear that the actual covenant of works has to be sought before the fall. Only in two points was this older doctrine of the covenant of works superseded by its later development.
—Geerhardus Vos, “The Doctrine of the Covenant in Reformed Theology” (De verbondsleer in de Gereformeerde theologie (Grand Rapids: “Democrat” Drukpers, 1891). This was Vos’ rectoral address at the Theological School of the Christian Reformed Church in Grand Rapids, Michigan. Trans. S. Voorwinde and W. Van Gemeren published privately by K. M. Campbell (1971) and rev. by R. B. Gaffin.