Otherwise God would be the author of sin, or a rational creature could commit every crime without guilt
Suppose God created a man with the same ignorance, the same leaning toward evil and resistance to good with which we are now born of Adam, and chose not to help him with any supernatural grace, as the scholastics commonly think could happen. That man would not love God or shape his acts and affections by the rule of right reason. He would give way to his desires in everything and would inevitably plunge into one crime after another as occasion arose, just as a child of Adam would do if he were left without any help from God's grace.
God would then be the author of sin, since he would have created a man who, through no fault of his own but simply because God chose to make him so, cannot avoid sin, rushes headlong into crimes of every kind by a flaw and drive in his nature, and cannot love his Creator as he ought.
Otherwise we would have to say there could be a rational creature not bound to know and love God, one that could defile itself with every impurity, give way to anger, excess and gluttony, assault its fellows with rape and murder, and do everything else the natural and eternal law forbids, and still not be guilty of any crime or sin. Both conclusions are utterly absurd and plainly involve impiety.
Latin
L. Posito enim quod Deus hominem aliquem creet cum eadem ignorantia, proclivitate ad malum, & repugnantia ad bonum, cum qua jam ex Adamo nascimur; nec ulla gratia supernaturali illum juvare velit, quod fieri posse censent communiter Scholastici, homo ille nec Deum diliget, nec actus & affectus suos ad normam rectae rationis componet, sed libidini suae in omnibus indulgebit, & in diversa flagitia, prout se dabit occasio necessario ruet; ut faceret homo ex Adamo natus, si omni gratiae divinae auxilio destitueretur. Ac proinde sic Deus erit author peccati; ut qui creaverit hominem, qui nulla sua culpa, sed quali illum Deo, formare visum fuit, peccatum vitare non potest, ac quodam naturae vitio & impetu in varia scelera sese praecipitem eat, nec creatorem suum, sicuti par est, diligere valet. Vel dicendum est dari posse creaturam rationalem, quae Deum agnoscere & amare non tenebitur, quaeque poterit se omni immunditia polluere, & irae luxuriae ac gulae indulgere, stuprisque & caedibus in sui similes grassari, & reliqua patrari quae lex naturae & aeterna vetat, nec tamen propterea ullius criminis & peccati rea fiet. Quorum utrumque est vehementer absurdum; & manifestam quandam impietatem involvit.