Cap. II Sol. Arg. 4: mark of vessels, not cause — seal of adoption / flight from iniquity
In that place Paul does not teach why vessels are elect to glory, but by what mark they are known. He stamps a double mark on them: one God alone can read — the seal of eternal adoption ("The Lord knows who are his"); the other men can see — flight from impiety and the practice of holiness and justice ("Let him depart from iniquity"; "If he cleanses himself, he will be a vessel unto honour").
Latin
Nam ille, in loco praedicto, non docet ex qua causa eligantur vasa ad gloriam, sed qua nota discernantur. Duplicem autem notam illis impressam dicit: Unam, quae Deo soli perceptibilis est, nempe signaculum aeternae adoptionis, Novit Deus qui sunt sui. Alteram, quae hominibus patet, fugam scilicet impietatis, & praxim sanctitatis & justitiae; Recedat ab iniquitate: Si se emundaverit, erit vas in honorem.