The Lord is called here the God of truth, which means that He is unlike the gods as the pagans imagined them, endowed with human “weaknesses”—in essence, vices—one of which is deceitfulness. Even more important, however, is that the One whose might surpasses everything draws us to Himself not by might, not by force, and not by the prospect of receiving wealth and prosperity from Him, but by truth. Truth seems so unimportant to the many people accustomed to saying, “If you do not cheat, you will not sell,” or, “The simpleton tells the truth, so everyone makes him carry the water.” But the Lord offers us another kind of strength, revealed amid apparent weakness and contrary to all familiar notions.

It is probably no accident that after the call to offer sacrifices of righteousness, the psalmist prophetically mentions bread and wine, which the Son of God, who sacrificed Himself, would call His Body and Blood...

The fourth psalm speaks of three things that are of the greatest importance in human life: truth, goodness, and peace. Without them, life itself is scarcely possible; without them, it seems a dark and painful existence. And the psalmist connects all this with the name of the Lord. Rejecting falsehood and vanity, he calls himself and all people to offer a “sacrifice of righteousness.” Truth thus becomes for him a form of service to God. He sees goodness in God Himself and asks Him to let the light of His face shine. David calls everything else vanity, because it passes without a trace; only the Lord’s light endures forever. Finally, he sees peace and joy in God’s help and protection, in the fact that God does not leave a person without His care. Thus prayer becomes for David the fulfillment of the first commandment.