Universal grace is an external benefit; particular grace works within
Thesis XXXIII. From what has been said it is clear enough that these theologians do not mean by universal grace any grace inhering in people. They mean only an external benefit of God: he handed his Son over to death so that divine justice might be satisfied for the sins of all, and, his justice being thus appeased, he calls people from outside to share in the salvation that Christ won for them by his death.
By particular grace, on the other hand, they chiefly mean the gifts and helps of God by which he acts within people, works conversion and faith in them, and in the end makes them actually share in eternal salvation.
Latin
XXXIII. Ex dictis vero satis patet, Theologos istos nomine gratiae universalis non intelligere gratiam aliquam in hominibus inhaerentem, sed tantum externum quoddam Dei beneficium, quo filium morti tradidit, ut divinae justitiae pro peccatis omnium hominum satisfieret, & quo justitia ejus ita pacata, homines extrinsecus vocat ad communionem salutis, quam Christus illis morte sua peperit. Et contra per gratiam particularem illos praecipue designare dona & auxilia Dei, quibus intus in hominibus agens in illis conversionem & fidem operatur, illosque tandem reipsa salutis aeternae participes efficit.