The law of the LORD is perfect, converting the soul: the testimony of the LORD is sure, making wise the simple.
Read Chapter 19
Augustine of Hippo
8. "The law of the Lord is undefiled, converting souls" (ver. 7). The law of the Lord, therefore, is Himself who came to fulfil the law, not to destroy it; an undefiled law, "Who did no sin, neither was guile found in His mouth," not oppressing souls with the yoke of bondage, but converting them to imitate Him in liberty. "The testimony of the Lord is sure, giving wisdom to babes." "The testimony of the Lord is sure;" for, "no man knoweth the Father save the Son, and he to whomsoever the Son will reveal Him," which things have been hidden from the wise and revealed to babes; for, "God resisteth the proud, but giveth grace to the humble." ...
The law. As the sun gives light to the world, so the law serves to direct mankind, and is another most powerful motive for us to praise God. This raises our hearts and minds still more perfectly to him, recalling us from our wanderings, and confirming our knowledge. Light is necessary for the body, and the law for the soul. The prophet admires eight characteristics of this divine law, which he designates by different names; as in the 118th psalm, some things relate only to the evangelical law, which converts souls, (Berthier) and lasts for ever, ver. 10. (Haydock)
The law of nature and of Moses are nevertheless also commended, (Theodoret) inasmuch as the morality is always the same; and some faith in Christ, to come, or already past, is requisite under every dispensation. Hence he is called the Lamb slain from the beginning. (Haydock)
Unspotted. Hebrew and Septuagint, "irreprehensible. "(Calmet)
Who indeed could pretend to find any fault with it, since it comes from God? (Haydock)