Whenever we think we’ve achieved lasting grace and others have not, a spiritual problem exists, and not for the unwashed masses:
50. Ultimately, the lack of a heartfelt and prayerful acknowledgment of our limitations prevents grace from working more effectively within us, for no room is left for bringing about the potential good that is part of a sincere and genuine journey of growth. [Evangelii Gaudium 44]
Remember, grace does not mean full and immediate stature:
Grace, precisely because it builds on nature, does not make us superhuman all at once. That kind of thinking would show too much confidence in our own abilities. Underneath our orthodoxy, our attitudes might not correspond to our talk about the need for grace, and in specific situations we can end up putting little trust in it. Unless we can acknowledge our concrete and limited situation, we will not be able to see the real and possible steps that the Lord demands of us at every moment, once we are attracted and empowered by his gift. Grace acts in history; ordinarily it takes hold of us and transforms us progressively. [In the understanding of Christian faith, grace precedes, accompanies and follows all our actions (cf. Council of Trent, Session VI, Decree on Justification, ch. 5: DH 1525)] If we reject this historical and progressive reality, we can actually refuse and block grace, even as we extol it by our words.
Skeptics might consult the biographies of the saints, and not necessarily their arguments against heretics. Take note of how their own journeys progressed.