Psalms 19:9 - Matthew Poole's English Annotations on the Holy Bible

The fear of the Lord; by which he understands not the grace of God's fear, as this phrase is commonly taken; nor the whole worship of God, as it is taken Psalms 34:9,11 Mt 15:9; but the law and word of God, which is the only thing that is here commended, and which is meant by all the other parallel titles of his testimony, and statutes, and commandments, and judgments, and consequently by this of his fear, which is as it were hemmed in within them. And this may well be so called by a usual metonymy, because it is both the object, and the rule, and the cause of this grace of holy fear, as God himself is called fear for the like reason, Genesis 31:53, and in the Hebrew, Psalms 76:1. Clean, i.e. sincere, not adulterated with any mixture of vanity, or falsehood, or vice; not requiring nor allowing any uncleanness or wickedness, as the religion of the Gentiles did. Enduring for ever; constant and unchangeable, the same for substance in all the ages of the church and the world: which is most true, both of the moral law, and of the doctrine of God's grace and mercy to sinful and miserable man; which two are the principal parts of that law, of which he here speaks, as is evident from the whole context. For as for the difference between the Old and the New Testament, that lies only in circumstantial, and ceremonial, or ritual things, which are not here intended; and that alteration also was foretold in the Old Testament, and consequently the accomplishment of it did not destroy, but confirm, the certainty and constancy of God's word. This also is opposed to human laws, wherein there are and ought to be manifold changes, according to the difference of times, and people, and circumstances. The judgments of the Lord, i.e. God's laws, frequently called his judgments, because they are the declarations of his righteous will, and as it were his legal or judicial sentence by which he expects that men should govern themselves, and by which he will judge them at the last day.