What does Psalm 19:7 mean?
Although creation points to the Creator (Psalm 19:1; Romans 1:18–20), it does not provide a complete picture of His attributes and will. Creation was placed under a curse when Adam and Eve sinned, so at times it may present a distorted picture of God. For example, the recurring seasons show that He is faithful and benevolent, but natural disasters may lead humans to picture the Creator as cruel. However, as David states in this verse, "the law of the LORD is perfect."David did not have the whole Bible to consult, but he had the full record of the statutes and precepts God had given to Israel. The law that God had given to Israel in written form was flawless. As such, it can revive the soul. It gives life to those who heed it and revival when the human spirit is downcast. David also affirms that "the testimony of the LORD is sure." This is a reference, in part, to the Ten Commandments. They impart wisdom to the humble, those who exercise a childlike submission to them. The Ten Commandments imparted to Israel the wisdom to know right from wrong. However, Israel did not always choose to obey them.
Psalm 19:7–14 introduces the law of the Lord—meaning Scripture—as God's perfect revelation of Himself and His will. The prior passage identified nature as a revelation of God. Psalm 119, as well, extols God's Word as His perfect revelation and cites the blessings which come to those who love and obey it.
David refers to the details of creation as evidence for God's power and design. The appearance and function of nature are evidence of God's majesty. The second half of this psalm also celebrates God's revelation, but in the form of His Word. The law, precepts, and commandments of God are hailed for their perfection and benefit.