Petrus van Mastricht begins his treatment of the doctrine of God by means of brief exegetical comments on Hebrews 11:6: “for whoever would draw near to God must believe that he exists and that he rewards those who seek him.”

According to Mastricht, this verse reveals three truths about God that are essential to saving faith insofar as they persuade us to seek God “as our highest end.” Those truths are: “(1) God exists; (2) he is such a God who is perfectly sufficient for himself and for us; and (3) he is such a God who is able and willing to share this sufficiency of his with us through his efficiency or operations” (Theoretical-Practical Theology, vol. 2, p. 43).
The first truth is a simple restatement of Hebrews 11:6. The one who would draw near to God must believe “that he exists.”
The second truth, though not a simple restatement of Hebrews 11:6, follows no less directly from the verse. “He rewards” those who draw near to him by faith by giving them what they seek, namely, “him.” God, according to Hebrews 11:6, is the all-sufficient, all-satisfying reward of those who seek him, “the blessed and only Sovereign” (1 Tim 6:15).
The third truth, that God “is able and willing to share this sufficiency of his with us through his efficiency or operations” again follows from Hebrews 11:6. This verse identifies God not only as one who exists—indeed blessedly so—but also as one who acts: “he rewards those who seek him.” Our willing act of pursuing God by faith is crowned by his willing act of rewarding us with himself.
God in his being, wellbeing, and agency is thus the threefold object of saving faith according to Mastricht. Saving faith believes that God is. Saving faith also believes something about what God is, i.e., that “he is such a God” in his blessed being and blessed-making works.
Mastricht’s exposition of the being, attributes, and triunity of God in all its exegetical, dogmatic, polemical, and practical detail is an exposition of these three truths, ordered to building up saving faith in its pursuit of God as its highest end. It is, moreover, a highly compelling exposition that I cannot recommend highly enough.