John Calvin Commentary Psalms 51:6

"Behold, thou desirest truth in the inward parts; And in the hidden part thou wilt make me to know wisdom." — Psalms 51:6 (ASV)

Behold, thou hast desired truth, etc. This verse confirms the remark we already made: that David was far from seeking to invent an apology for his sin when he traced it back to the period of his conception. Instead, he intended by this to acknowledge that from his very infancy, he was an heir of eternal death.

He thus represents his whole life as having been liable to condemnation. He is so far from imitating those who arraign God as the author of sin, and impiously suggest that God might have given humanity a better nature, that in the verse now before us, he contrasts God’s judgment with our corruption. This insinuates that every time we appear before God, we are certain of being condemned, since we are born in sin, while He delights in holiness and uprightness.

He goes further and asserts that to meet God's approval, it is not enough for our lives to be conformed to the letter of His law unless our heart is clean and purified from all guile. He tells us that God desires truth in the inward parts, intimating to us that secret, as well as outward and gross sins, arouse His displeasure.

In the second clause of the verse, he aggravates his offense by confessing that he could not plead the excuse of ignorance. He had been sufficiently instructed by God in his duty. Some interpret בסתום, besathum, as if he here declared that God had revealed secret mysteries to him, or things hidden from human understanding. He seems rather to mean that wisdom had been revealed to his mind in a secret and intimate manner.

One part of the verse corresponds to the other. He acknowledges that it was not a mere superficial acquaintance with divine truth which he had enjoyed, but that it had been closely brought home to his heart. This rendered his offense all the more inexcusable. Though privileged so highly with the saving knowledge of the truth, he had plunged into the commission of brutish sin and, by various acts of iniquity, had almost ruined his soul.

We have thus set before us the spiritual process of the Psalmist at this time. First, we have seen that he is brought to a confession of the greatness of his offense. This leads him to a sense of the complete depravity of his nature. To deepen his convictions, he then directs his thoughts to the strict judgment of God, who looks not to the outward appearance but to the heart. Lastly, he turns his attention to the unique aspects of his case, as one who had enjoyed an extraordinary measure of the gifts of the Spirit and, on that account, deserved the severer punishment.

This spiritual process is one we should all strive to imitate. If we are conscious of having committed any one sin, let it be the means of recalling others to our memory, until we are brought to prostrate ourselves before God in deep self-abasement.

And if it has been our privilege to enjoy the special teaching of the Spirit of God, we ought to feel that our guilt is additionally heavy, having sinned in this case against light and having trampled underfoot the precious gifts with which we were entrusted.