Psalms 19:7

The law — The doctrine delivered to his church, whether by Moses, or by other prophets. Having discoursed hitherto of the glory of God shining forth in, the visible heavens, he now proceeds to another demonstration of God's glory, which he compares with and prefers before the former. Perfect — Completely discovering both the nature and will of God, and the whole duty of man, what he is to believe and practice, and whatsoever is necessary to his present and eternal happiness. Whereas the creation, although it did declare so much of God, as left all men without excuse, yet did not fully manifest the will of God, nor bring men to eternal salvation. Converting — From sin to God, from whom all men are naturally revolted. Testimony — His law, so called because it is a witness between God and man, what God requires of man, and what upon the performance of that condition, he will do for man. Sure — Heb. faithful or true, which is most necessary in a witness: it will not mislead any man, but will infallibly bring him to happiness. Simple — Even persons of the lowest capacities.