John Calvin Commentary Psalms 119:34

"Give me understanding, and I shall keep thy law; Yea, I shall observe it with my whole heart." — Psalms 119:34 (ASV)

Make me to understand. We are informed here that true wisdom consists in being wise according to the law of God, so that it may preserve us in fear and obedience to Him. In asking God to grant this wisdom to him, he acknowledges that people, because of their natural blindness, aim for anything rather than this.

Indeed, it is quite foreign to the common understanding of humanity to strain every nerve to keep God’s law. The world considers only those wise who look out for their own interests, are sharp and shrewd in worldly matters, and who even excel in the art of deceiving the simple.

In opposition to such a view, the prophet declares people to be devoid of true understanding as long as the fear of God does not prevail among them. For himself, he asks for no other wisdom than to surrender himself entirely to God’s direction. At the same time, he acknowledges this to be the special gift of God, which no one can obtain by their own power or strategy; for if everyone were capable of teaching themselves in this matter, then this petition would be unnecessary.

Moreover, as the observance of the law is not a common occurrence, he employs two expressions in reference to it. He essentially prays, “Lord, it is a high and hard thing to keep Your law strictly as it should be kept, which demands from us a purity beyond what we are able to achieve; yet, depending on the heavenly illumination of Your Spirit, I will not stop trying to keep it.”

The following, however, makes the meaning clearer: “Give me understanding to keep and observe Your law with my whole heart.” Mention is made of the whole heart, to show us how far those are from the righteousness of the law who obey it only outwardly, doing nothing blameworthy in the sight of people.

God puts a restraint primarily on the heart, so that genuine uprightness may flourish there, whose fruits may then appear in their life. This spiritual observance of the law is very convincing evidence of the need to be divinely prepared and shaped for it.