Most of the world’s religions have some kind of doctrine of divine revelation upon which the teachings of their particular system are based. However, the revelation given in most of these other religions is not, in the final analysis, dependable. For example, there are many passages in the Qur’an suggesting that Islam’s Allah is not finally knowable — that he can choose whatever characteristics he wants to have and therefore human beings cannot have a true knowledge of his character. Similarly, the pagan gods portrayed in religions both ancient and modern are capricious, changing their demands, actions, or emotions on a whim, leaving their servants unable to know what is expected of them.
The God of the Bible, however, is far different. His character remains consistent, for He is who He is and does not change like the blowing wind; there is no shadow of turning in Him (James 1:17). Because He is not capricious, He can be known. He can be trusted. His words are a true revelation of Himself, and we need not fear that He will act arbitrarily. Such was good news for the ancient Israelite, and it remains good news for us today.
Psalm 19 assumes the knowability of the Lord when it emphasizes the surety of His laws. In a culture surrounded by people who followed temperamental, unpredictable deities, God spoke to Israel, giving rules that are “righteous altogether” (v. 9). If these rules were based on whimsy, they could not be righteous altogether, because there would always be the possibility that the Lord might change His mind and render unrighteous that which was formerly righteous. But God’s statutes are based on an unchanging standard — nothing other than the character of the Lord Himself.
Even though Psalm 19:7–11 refers to “the law of the Lord” specifically (v. 7), David’s understanding of the term law in this instance more broadly refers to the entire body of divinely inspired teaching. This teaching is adept at “reviving the soul” (v. 7) — it calls men and women to repentance and imparts life by the Spirit’s power. It warns us against error and points us to a sure reward that we receive by faith (v. 11). It can accomplish all this because it has been promised by the life-giving Creator who never changes.