In his book The Call of Grace, Norman Shepherd promotes the idea that all covenants have conditions which Man has to fulfill in order to partake of the promises of the covenant. Shepherd's monocovenantalism entails the total confusion of grace and works. In the name of navigating a third way between legalism and antinomianism (pp. 8-9), Shepherd creates a monstrosity where one is saved by grace, but then one has to persevere in order to remain in grace. One wonders whether Shepherd realizes that this is the Roman Catholic position. Rome has never once taught that one is saved by works, but she has always taught that one is saved by grace AND faith "formed by love," the performing of works in accordance with one's faith.
I would like to look at this issue of "conditionality" as to how Shepherd has totally muddled the issue. The PRCA (Protestant Reformed Churches of America) of course think that this issue of "conditionality" is basically the problem with the Federal Vision: the "heresy of conditional covenant," while totally ignoring the fact that in some sense, faith must be a condition. The PRCA are irrational in their idiosyncratic doctrines, and ideas that one can have an absolutely "unconditional" covenant and faith are contradictory to basic reason.
The concept of conditions merely signifies that they are necessary and/or sufficient for the consequent(s) to occur. For a sufficient condition, if "condition x," then "result y." For a necessary condition, no "condition x," no "result y." It does not say in what sense it is necessary or sufficient. Faith for example we have said is the instrumental condition for salvation. It is not the grounds for salvation, but the manner of how salvation comes about. This drawing of distinctions is necessary, because as we shall see with Shepherd, the failure to draw distinctions result in heresy.
Shepherd treats "conditions" as something that Man must do, as basically "human responsibility" (p. 9). Immediately here we see that that is the wrong definition. Just because something is a condition does not mean that Man is responsible for it. If I say that it is a necessary condition that the Holy Spirit regenerates the elect, in order that they may be saved, is there anything humans have to do in the entire process? Of course not! Shepherd starts off with the wrong idea of "condition," and things just go south from there.
In his discussion of the Abrahamic Covenant, Shepherd claims that there are 5 requirements which had to be met in order for God to fulfill His promises to Abraham. The first requirement is that circumcision is necessary. Furthermore, since circumcision is not meant to be "merely outward and physical" (p. 15), the requirement of circumcision means God was "requiring the full scope of covenant loyalty and obedience all along the line" (p. 15). Right off, the extension of circumcision to the full scope of covenant obedience is just a total confusion of sign and the thing signified. Even worse than that is Shepherd doesn't even seem to realize that the inward circumcision is not obedience but regeneration, as the correspondence between circumcision and baptism in Col. 2: 13 show. What else does "God made us alive" mean except the act of regeneration? Circumcision and baptism both are supposed to function as the sign of regeneration or inward circumcision, and thus Shepherd is in error even if we admit that circumcision is a "Shepherdite-condition."
Circumcision however is not a Shepherdite-condition. Rather, it is a requirement in the sense that it is a sign of something required, i.e. regeneration. Just as baptism does not save, but rather what it signifies, regeneration, saves, so likewise this requirement of circumcision is not a requirement for salvation, but a requirement that logically (not necessarily temporally) follows regeneration. It is an a posteriori condition, not an a priori condition, just like good works. An a posteriori condition merely means it is the necessary consequent of faith. A person breathes if he is alive, thus he does not "fulfill the condition" of breathing in order to be alive, but that he is alive so he therefore breathes. The failure to breathe evidences that the person is dead, not alive. Likewise, in this sense refusal to circumcise does not mean that a person is not regenerated, but rather that it evidences an unregenerate heart.
The other Shepherdite-conditions are that Abraham needs to have faith, he needs to have a "living and obedience faith," and he needs "to walk before the Lord and be blameless" (pp. 15-6), and the fulfillment of the promises of the land promise for example depended upon the obedience of the Israelites. Regarding faith, Shepherd refuses to distinguish between instrument and ground. The next two "requirements" Abraham has to do are a posteriori conditions. The last requirement shows the conflation of the Abrahamic and Mosaic covenants. The Abrahamic promise of land refers to the promised land of Canaan as a type of heaven, while the physical land itself is a typological fulfillment in the Mosaic Covenant, and thus not the same.
This is just a sample of the problems with this book. Shepherd routinely refuses to make distinctions and he conflates issues together, and in so doing creates heresy. All covenants have conditions, that's true. But not all conditions are conditions. And most certainly conditions are not always indications of human responsibility. Conditionality is merely a logical function, and says nothing about who and how the conditions are supposed to be met.