"The gift of God's love is ours for the taking. I am a Roman Catholic. But the most liberating idea I have ever heard I first learned from Martin Luther. Pope John Paul II told the German Lutheran bishops that Luther was profoundly right about this idea. He said that Catholic teaching affirms it just as strongly and that there was no contradiction between Protestant and Catholic theology on this terribly important point, which was the central issue of the Protestant Reformation. I speak, of course, about "justification by faith" and its consequence, which Luther called "Christian liberty" or "the liberty of a Christian" in his little gem of an essay by that name.
Let us be careful to approach the point in the right way. I think most misunderstandings begin at this very first step. Let's begin with a solid certainty: God is love. God is a lover, not a manager, businessman, accountant, owner, or puppet-master. What He wants from us first of all is not a technically correct performance but our heart. Protestants and Catholics alike need to relearn or reemphasize that simple, liberating truth... it liberated me just as it had the Catholic Augustinian monk Luther 450 years earlier. The crucial sentence for me was: "We may think God wants actions of a certain kind, but God wants people of a certain sort." (Mere Christianity)
The point is amazingly simple, which is why so many of us just don't get it. Heaven is free because love is free. It is ours for the taking. The taking is faith. "If you believe, you will be saved." It is really that simple. If I offer you a gift, you have it if and only if you have the faith to take it.
The primacy of faith does not discount or denigrate works but liberates them. Our good works can now also be free - free from the worry and slavery and performance anxiety of having to buy Heaven with them. Our good works can now flow from genuine love of neighbor, not fear of Hell. Nobody wants to be loved merely as a means to build up the lover's merit pile. That attempt is ridiculous logically as well as psychologically. How much does Heaven cost? A thousand good works? Would 999 not do, then? The very question shows its own absurdity. That absurdity comes from forgetting that God is love.
The whole point of justification by faith is God's scandalous, crazy, and wonderful gift of love." - Peter Kreeft "The God Who Loves You" p. 23-25
Not exactly an analytical take on the issue, but a good read nonetheless.
The Roman Catholic condemnations seem to be on the issue of faith being the sole basis of our justification. This leaves works at least some spot for our trust and assurance of salvation. BUT what Kreeft and others have done, for the sake of sanity, is really said that faith plus the habitus or innate regenerated inclination towards love are the ground of our justification. So as long as you can say 'I love God' and in some way whatsoever mean it, you can have a grounding in your faith, because it is faith formed by love. Thus the anathemas of Trent are just barely dodged, and one can be a Catholic of the Pascalian/Jansenist flavour and remain orthodox.
According to J.V. Fesko, this also has a similitude to some outliers in the Reformed Tradition, such as Jonathon Edwards, Albert Ritschl, and others in the early 20th century who emphasized mystical union and the Fatherly judgments of God / Congruent merit, rather than the juridicial / imputation doctrines. Or in other words, if you heap up the Congruent merit, and believe that every time God judges a believers work he is polishing the spots from it (to use Calvin's analogy), and you believe that he imputes perfection to the person's infused faith, hope and love, THEN you can have some sort of assurance. But again, this is just barely dodging Trent, and probably outside the mainstream of Roman Catholic theology.