What strikes me about the way of grace in The Tree of Life is how Malick evokes grace as the grain of the universe. This is difficult to put into words, so you'll have to watch (or rewatch) the film, but Malick uses the visual poetry of the film to create an ontological feeling, how grace saturates every moment, how grace permeates everything. The way of nature, by contrast, cuts against this grain, tries to dominate and control rather than surrender and flow with the grain of grace.
All that to say, I think The Tree of Life is one of the most profound depictions of "the grain of the universe," the fusion of morality and ontology.
