This urge to sacrifice, to relinquish this for that, to choose one way or line of conduct and thus sacrifice another way, to lose in order eventually to gain—such is the underlying story of evolution. This needs psychological understanding. It is a governing principle of life itself, and runs like a golden pattern of beauty through the dark materials of which human history is constructed. When this urge to sacrifice in order to win, gain or salvage that which is deemed desirable is understood, then the whole clue to man’s unfoldment will stand revealed. This tendency or urge is something different to desire, as desire is academically understood and studied today. What it really connotes is the emergence of that which is most divine in man. It is an aspect of desire, but it is the dynamic, active side and not the feeling, sensuous side. It is the predominant characteristic of Deity.(Esoteric Psychology II, p. 97)