Herman Bavinck’s valuable survey of Christian doctrine, Our Reasonable Faith (Grand Rapids: Eerdmans, 1956) has a wonderful section on the state of man in Eden before the fall. Let me summarize his summary from pages 216-220.
Bavinck starts by noting that we have to distinguish between the “condition in which the first man was created and the destination to which he was called.” That is, “the image of God” in man “had to come to a constantly richer and fuller unfolding of its content by means of its striving towards its destination.” “Man had to cultivate the earth so that it would more and more become a revelation of God’s attributes.” Adam’s work wasn’t some endless, aimless toil, but it had a developmental intention, a “course of action, final purpose, destination.” “If, then, man at his creation was called to work, that implies that he himself and the people who should issue from him should enter into a rest after the work.” Rest was the destination.
Further: “The final purpose of man lay in the eternal blessedness,” to praise and glorify God. However, Adam did not live in heaven, but in paradise. He was in a state where there was night and day, whereas in heaven there is neither (Rev 21.25 and 22.5). Adam was in a state where there was work to be done; heaven is rest. Adam was in a state where there was marriage; heaven has no marriage (Matt 22.30). Adam had a natural, earthly body; heaven’s citizens have a spiritual body (1 Cor 15). Adam could stray, sin, wander; those in heaven cannot and do not. Adam was placed at the beginning of a road, not the end; “he was able-not-to-sin, but not-yet-not-able-to-sin.” “He did not yet possess eternal life which cannot be corrupted and cannot die, but received instead a preliminary immortality whose existence and duration depended upon the fulfillment of a condition.” One thing Adam lacked – spiritually and physically – was “absolute certainty.”
Does this mean that Adam needed to mature and one day grow up to faith[fullness]? “We must maintain that” Adam was “not at first a small, innocent child that had to develop into maturity.” “He was immediately created in the image of God in true knowledge, righteousness, and holiness.” How then would Adam before the fall reach that certain state of blessedness? “In order to enter into the rest of God he first had to finish God’s work. The entrance to the Sabbath is opened by the six days of work.” Moreover, whether Adam “was to reach that appointed destination was made dependent upon his own choice and upon his own will.” “One comes to eternal life by way of work.”
Of course, Bavinck goes into even more depth in Reformed Dogmatics, where he says clearly: the matter and substance of the doctrine of the covenant of works is certain. Also, as I’ve noted on here before, Kuyper and Vos sound very similar to the above, because the covenant of works runs through the veins of Dutch Reformed orthodoxy.