“The first covenant made with man was a covenant of works, wherein life was promised to Adam, and in him to his posterity, upon condition of perfect and personal obedience” (7.2).
The WCF tenet is that if Adam doesn’t disobey, then he merits eternal
life for his people. But if Adam merits eternal life  for his people,
then it follows that Christ does not. Thus, the Westminster devils just
vitiated the atonement by means of this cockamamy conjecture. It is far
from logical to vainly speculate about the merit a hypothetical or
theoretical, obedient Adam. For if Adam obeys, there is no Fall. And if
there is no Fall, there is no Atonement, and if there is no atonement
there is no gospel. Obedient Adam=No Fall. No Fall=Vitiated Atonement.
Vitiated Atonement=No Gospel. Thus: Obedient Adam=No gospel.
For if Adam had indeed fulfilled the law, then he would have usurped
the throne of Christ, and his people would apparently be thanking God
for enabling creature-man to steal Christ’s redemptive glory. This is
the worship of man, plain and simple. It is antichristian blasphemy to
assert the possibility of a mere creature obtaining the SAME GLORY as
Jesus Christ. This cheapens and profanes the absolute uniqueness and
exclusivity of the work of Jesus Christ for His people. The everlasting-
righteousness-establishing, eternal-life-demanding, work of Jesus
Christ on behalf of His people is met with the Christ-dishonoring,
“Yeah. Well, Adam had the power to accomplish the same thing as Christ APART from suffering for the sins of his people.”
It is statements like this that make me think, no wonder many
adherents of the WCF find it so mysteriously perplexing how Adam fell.
One truly does wonder if comments to this effect do not reflect a secret
desire that Adam had passed the supposed “probationary period” and had
thus robbed Christ of His glory by receiving glory for saving his people
from a hypothetical fall. Those who attribute to the creature (i.e.,
Adam) qualities of character that belong to Christ ALONE, have not in
mind the glory of God, but the glory of men.
 In the chapter "Adam's Reward: Heaven or Earth?," Mark A. Herzer writes:
"What did God promise Adam? The Westminster Confession of Faith declares that 'life was promised to Adam' (7.2) and the Shorter and Larger Catechisms indicate that God entered into a 'covenant of life with him' (LC, #20; SC, #12). What is not explicitly stated is the kind of life promised to Adam. No divine would have disagreed with those statements because they were not controversial. But what kind of life would Adam have received had he perfectly obeyed? Not surprisingly, a diversity of answers surrounded this question. ...
Though they [Thomas Goodwin and Francis Turretin--CD] developed different theological structures to this question, it becomes clear that they both worked with the concept of the covenant of works, or more precisely, foedus naturae. Both carefully highlighted the graciousness of both this estate and Adam's reward. Goodwin emphasized the distinction between nature and grace in his position while Turretin did not go so far. They preserved the gracious character of the covenant of works while utilizing typical scholastic distinctions. Though some of the language (especially in Goodwin) came from some of the Medieval distinctions, they nonetheless utilized them to advance Reformed orthodoxy. Of the two, Goodwin is the more interesting on account of his careful emphasis on Adam in the foedus naturae (Drawn into Controversie: Reformed theological diversity and debates within seventeenth-century British Puritanism by Michael A.G. Haykin (Editor), Mark Jones (Editor); pp. 162, 164-165).
Whether the supposed "promised life" to Adam be temporal (Goodwin) or eternal (Turretin), the Biblical fact remains that BOTH of these vain and speculative views rob Jesus Christ of His redemptive glory, and attempt to erase Him from history.