This step, as Lewis puts it here, is the progression of mankind from awe, to connecting awe with ethics.
Is it possible know if this was reveled, or if it was in our hearts all along?
My gut says that it may have been a bit of both.
But I am willing to be wrong here.
Understand: Humans have a tough time avoiding morality and ethics – as they should.
Judged by its fruits, this step is a step towards increased health. And though logic does not compel us to take it, it is hard to resist—even on Paganism and Pantheism morality is always breaking in, and even Stoicism finds itself willy-nilly bowing the knee to God. Once more, it may be madness—a madness congenital to man and oddly fortunate in its results—or it may be revelation.
-C.S. Lewis, The Problem Of Pain (Amazon)