Rome's proof from Matthew 22 and Luke 15: the just are equal to angels, and angels know sinners' repentance
The theologians of the Roman school also argue that the saints triumphant in heaven are not ignorant of what men do or of what happens to them in this lower world, and that even men's thoughts are not hidden from them, because these things do not escape the knowledge of the angels.
For Christ himself testifies that the just in heaven will be "equal to the angels" (isangeloi), "as the angels of God," in the twenty-second chapter of Matthew (Matthew 22:30; compare Luke 20:36). Since they are to be equal to the angels, they argue, we must not think that angels surpass them in knowledge of our affairs.
And they take it to follow that what happens on earth, even the inner movements and feelings of human hearts, is known to the angels of heaven, because the angels are said to rejoice "over one sinner who repents more than over ninety-nine righteous persons" (Luke 15:7, 10). If the angels see sinners' repentance, they certainly know what happens in the world, not only outwardly but inwardly too, in the sinner's heart, where true repentance and sorrow for sin reside.
Latin
C. Praeterea Sanctos in caelo triumphantes non ignorare quae homines agunt, & quae iis accidunt in hoc mundo inferiori; imo ab iis occultas non esse hominum cogitationes, inde probant Scholae Romanae Theologi, quod ista cognitionem Angelorum non effugiunt. Christus enim ipse testatur justos in caelis fore ἰσαγγέλους sicut Angelos Dei; apud Matthaeum capite vigesimo secundo. Ac proinde cum debeant Angelis aequales esse, non putandum est illos ab Angelis notitia rerum nostrarum superari. Jam vero caelestibus Angelis nota esse quae in terris aguntur, adeoque ipsos cordium humanorum interiores motus atque affectus, ex eo sequi existimant quod dicuntur gaudere super uno peccatore poenitentiam agente, magis quam super nonaginta novem justis. Si enim peccatorum poenitentia ipsis perspecta est, utique norunt quid in mundo agatur; non modo foris, sed intus etiam in corde peccatoris, in quo est vera poenitentia & dolor de Peccatis. Luc. 15. 10.