The grace required is regenerating grace itself: Placaeus and Ames
Thesis XXV. The Protestants do not merely say that the grace by which faith is produced is needed for every good work, and that no one can offer the natural law a true obedience pleasing to God without it. They also teach openly enough that the grace without which no one can act well, or do even one truly good work, is regenerating and justifying grace itself.
This can be seen especially in Josué de la Place, who denies that a man can avoid sinning without the grace of regeneration. His words are these: 'As for moral actions, those the law commands or forbids, Bellarmine multiplies questions needlessly. We bring our whole dispute with the Papists over free choice in the state of sin back to this one question: can an unregenerate man avoid sinning without the grace of regeneration? The Papists say yes; we say no' (treatise On free choice, page 201).
What we read in Ames's Bellarmine Disarmed agrees with this. 'First,' he says, 'our divines teach that man can do nothing of spiritual good before he is born again, whereas Bellarmine requires only the help of a grace that persuades and assists. Second, our divines require for spiritual good the help that is proper to those effectually called, whereas Bellarmine means a general help that is lacking to no one at the right place and time' (book 4, On free choice, chapter 3).
There Ames includes under 'spiritual good' everything truly good in the moral order. For, as I showed above, the Protestants count nothing in this order as truly good unless it proceeds from a sincere love of God and so belongs in some way to godliness and the spiritual worship of God.
Latin
XXV. Neque simpliciter asserunt Protestantes gratiam per quam fides ingeneratur, necessariam esse ad quodvis bonum opus, & neminem sine illa verum & Deo gratum obsequium legi naturali praestare; sed praeterea satis aperte docent, gratiam illam sine qua nemo bene operari potest, & vel unicum opus revera bonum efficere, esse ipsam gratiam regenerantem & justificantem. Id praesertim videre est apud Josuam Placeum, qui negat hominem posse non peccare sine gratia regenerationis. Haec enim sunt illius verba. Ad morales quod attinet actiones, quas, scilicet, lex aut praecipit aut prohibet, multiplicat quaestiones Bellarminus sine ulla necessitate. Nos ad hanc unam quicquid nobis est cum Pontificiis controversiae de Libero Arbitrio in statu peccati revocamus, Possit ne homo irregenitus non peccare sine gratia regenerationis? affirmant Pontificii, nos negamus. Tractatu de libero Arbitrio pag. 201. Quibus consonat quod apud Amesium legitur in Bellarmino enervato. Primo, inquit, nostri docent nihil boni spiritualis efficere hominem posse antequam sit regenitus: sed Bellarminus auxilium gratiae suadentis & assistentis tantum requirit. Secundo, nostri illud auxilium requirunt ad bonum spirituale, quod est proprium efficaciter vocatorum: sed Bellarminus auxilium generale intelligit, quod pro loco & tempore nemini deest. Lib. 4. de libero Arbitrio cap. 3. Ubi sub nomine boni spiritualis complectitur quicquid vere bonum est in genere morum: quoniam, ut supra ostendi, Protestantes in hoc genere nihil revera bonum existimant, quod non ex sincera Dei dilectione procedat, adeoque ad pietatem & spiritualem Dei cultum aliquo modo pertineat.