Conclusion: the Lutherans keep what the Roman school means by sufficient grace
Thesis XVI. It is clear, then, from what has been said, that the theologians of the Augsburg Confession reject the division of grace into sufficient and efficacious, so common in the Roman school, yet affirm what most doctors of that school mean by sufficient grace.
That is: those who are not converted by the preaching of the Gospel lack no aid from God's side that their conversion requires and without which they could not be converted. And so even unbelievers who reject God's word are offered a grace fully enough to bring them to repentance and faith, if they do not refuse to use it.
Latin
XVI. Porro ex antedictis manifestum est, Augustanae Confessionis Theologos non admittere quidem distinctionem gratiae in sufficientem atque efficacem, quae in Schola Romana plurimum usitata est, sed tamen illud ponere quod per gratiam sufficientem plerique Scholae illius Doctores significatum volunt. Nempe illis qui per praedicationem Evangelii non convertuntur, nullum ex parte Dei deesse auxilium quod ad conversionem ipsorum necessarium sit, & sine quo converti non possint: adeoque incredulis ipsis verbum Dei rejicientibus eam offerri gratiam quae abunde sufficiat illis ad poenitentiam & fidem adducendis, si ea uti non recusent.