God cannot allow the sinner, or even the mere human, though he be sinless Adam, to merit. Merit puts God in the sinner’s, or the mere human’s, debt. This would be for God to “ungod” Himself [David Engelsma, PRTJ 46:1 (Nov 2012): 121].
To this, I will just point to my short post on the topic of covenant merit. If we are talking about covenant merit, which even the authors of Moses and Merit profess to hold, then Engelsma's concern with the use of "merit" is totally misplaced.
All humans have a grace of God in common. All humans alike are bound to God and to each other in a divine covenant of grace. God is bound, in His covenant, graciously, to the likes of Nero, Duke Alva, Hitler, Stalin, John Wayne Gacy, Richard Dawkins, and all those today whose rebellion against Him has reached the pitch of changing “the truth of God into a lie, and worship[ing] and serv[ing] the creature more than the Creator” (Rom. 1:25).
The authors put the blessing of God in the houses of all these wicked persons, where it may contend (successfully, the authors think) with the curse that God Himself has placed in these houses (see Prov. 3:33). (Ibid.)
"Common grace", at least the orthodox version of it, is not redemptive or salvific. Therefore, to say that a teaching of common grace is to bind rebellious sinners to God "graciously" unto salvation is a gross misrepresentation of what Brown and Keele mean by "common grace." If we can use the word "grace" to talk about non-redemptive grace before the Fall, then why is it that we cannot speak of non-redemptive "common grace" after the Fall? If one wants to restrict grace for the process of salvation, then one cannot claim that there is grace before the Fall, for Adam does not need to be saved before he fell.
In conclusion, Engelsma misrepresents Brown and Keele in their book Sacred Bond, he engages in all manner of redefinitions of words and concepts, and in so doing massacres the English language. He also shows his ignorance of what those who do not hold to his sectarian version of Covenant Theology actually believe in. It is fine if one disagrees with orthodox Reformed Covenant Theology, but it is not acceptable that one misrepresents one's opponents and recasts them in one's idea of what constitutes error without even showing understanding of what they hold to. Unfortunately, from my personal interaction with PRCA people, this is sadly what I have come to expect.