It frequently happens, however, that theology and philosophy are not contented with this. They then endeavor, after the manner of Plato and Hegel, to offer a rational explanation of the world. Or, while falling back upon the will of God, they make out of this will a Βυθός άγνωστος (deep unknown), as is done by Gnosticism, or a blind, irrational and unhappy will, as is done by Schopenhauer, or an unconscious and unknowable power, as is done by von Hartmann and Spencer. By his Christian faith Calvin was kept from these different forms of pantheism. It is true, Calvin upholds with the utmost energy the sovereignty of the divine will over and against all human reasoning. Predestination belongs to the divinae sapientiae adyta (shrine of the divine wisdom) which man may not enter and in regard to which his curiosity must remain unsatisfied; for they form a labyrinth from which no one can find the exit. Man may not even investigate with impunity the things God meant to keep secret. God wants us to adore, not to comprehend, the majesty of His wisdom.
Excerpted from Herman Bavinck's article, "Calvin and Common Grace"
Source: The Princeton Theological Review, Vol. 7, No. 3 (1909), p. 450, the parenthetical translations of Latin and Greek terms are mine.