Fear and Courage
This, indeed, is probably one of the Enemy's motives for creating a dangerous world--a world in which moral issues really come to the point. He sees as well as you do that courage is not simply one of the virtues, but the form of every virtue at the testing point, which means, at the point of highest reality. A chastity or honesty, or mercy, which yields to danger will be chaste or honest or merciful only on conditions. Pilate was merciful till it became risky.
~C.S. Lewis, The Screwtape Letters, Letter 29 (1942)
He made a strong resolution, defying in advance all changes of mood, that he would faithfully carry out the journey to Melidorn if it could be done. [...] The silent, purple half-light of the woods spread all around him as it had spread on the first day he spent in Malacandra, but everything else was changed. He looked back on that time as on a nightmare, on his own mood at that time as a sort of sickness. Then all had been whimpering, unanalysed, self-nourishing, self-consuming dismay. Now, in the clear light of an accepted duty, he felt fear indeed, but with it a sober sense of confidence in himself and in the world, and even an element of pleasure. It was the difference between a landsman in a sinking ship and a horseman on a bolting horse: either may be killed, but the horseman is an agent as well as a patient.
~C.S. Lewis, Out of the Silent Planet, Chapter 14 (1938)