Elizabeth Goudge said this quote

Progress in evil was quick and easy; Apollyon was not a chap who hid himself and he gave every assistance in his power. The growth in goodness was so slow, at times so flat, so dull, and like the White Queen one had to run so fast to stay where one was, let alone progress; and there were few men who dared to say they had found God. It was easy to be a clever sinner, for the race to an earthly visible goal was short to run, so impossibly hard to be a wise saint, with the goal set at so vast a distance from this world and clouded with such uncertainty.