Psalms 119:127

"Therefore," he says, "I love Your commandments above gold and topaz" [Psalm 119:127]. Grace has this object, that the commandments, which could not be fulfilled by fear, may be fulfilled by love...Therefore, they are above gold and topaz stones. For this is read in another Psalm also, "Above gold and exceeding precious stones." For topaz is a stone considered very precious. But they not understanding the hidden grace which was in the Old Testament, screened as it were by the veil (this was signified when they were unable to gaze upon the face of Moses), endeavoured to obey the commandments of God for the sake of an earthly and carnal reward, but could not obey them; because they did not love them, but something else. Whence these were not the works of the willing, but rather the burdens of the unwilling. But when the commandments are loved for their own sake "above gold and exceeding precious stones," all earthly reward compared with the commandments themselves is vile; nor are any other goods of man comparable in any respect with those goods whereby man himself is made good.