This is the perfection of parts Scripture praises
Thesis XXV. So the perfection the Schools usually call perfection of parts can rightly be ascribed to their obedience. They try to bring both the acts of the body and the affections of the mind into line with the whole law and every one of its precepts, and to do so steadily and with perseverance.
If this were not so, Scripture would certainly not credit believers with true righteousness and holiness, as it does in Ephesians 4 when it says they put on the new man, created after God in the righteousness and holiness of truth. A righteousness maimed and mutilated in the parts that belong to its very essence is no true righteousness.
This is the perfection for which Job and Noah are praised and which David has no qualms about claiming for himself. In those places 'perfection' means only the integrity and sincerity of these holy men; the Hebrew word Tham or thamim, which translators there render 'perfect', properly means whole and sincere.
Latin
XXV. Itaque jure merito potest eorum obedientiae tribui perfectio illa, quae perfectio Partium in Scholis appellari solet. Siquidem integrae legi, & universis illius praeceptis, tum corporis actus, tum animi affectus, idque constanter & perseveranter exigere conantur. Et certe, nisi hoc esset, scriptura fidelibus non tribueret justitiam & sanctitatem veram, dum ait, illos indui novo homine, qui creatur secundum Deum, in justitia & sanctitate veritatis, Ephes. 4. Nam vera justitia non est, quae respectu partium, ad essentiam justitiae omnino pertinentium, manca & mutila est. Et haec est illa perfectio cujus nomine laudantur Job & Noe, & quam David sibi ipsi tribuere non formidat. Etenim per perfectionem solum ibi designatur integritas atque sinceritas sanctorum istorum virorum. Siquidem vox Hebraea Tham sive thamim, quam ibi Interpretes per perfectum exponunt, integrum & sincerum proprie significat.