He with body waged a fight,This poem by W. B. Yeats (The Four Ages of Man) evokes the spiritual evolution of man according to the esoteric tradition. EARTH, according to occult science, is the fourth stage of man's spiritual evolution. Earlier, on SATURN, the basis of the physical body, the most developed part of man, was laid down. On SUN the heart was infused into the physical organism, and on MOON the mind. On EARTH man is meant to learn to steer his own ship with the rudder of his consciousness - some call it the 'ego'- or else to yield up the responsibility for his existence to somebody else - a WORLD DICTATOR, the leader of a cult, or to one kind of institution or other, etc.
But body won: it walks upright.
Then he struggled with the heart;
Innocence and peace depart.
Then he struggled with the mind;
His proud heart he left behind.
Now his wars on God begin;
At stroke of midnight God shall win.
In each stage of his spiritual evolution, there is a struggle between the temptation to remain in the status quo or to yield to the possibilities of what the spirit is attempting to accomplish through matter. The spirit triumphs, and so man walks instead of continuing to crawl. He is given a heart, but it is of the nature of his spiritual evolution that he cannot remain in a state of innocence. Man must move on to the world of experience and from there to the dual possibilities the Mind is capable of. The choice on EARTH is either to consolidate what he has learned and which he is capable of applying endlessly to the earth (and maybe even to the cosmos) or to surrender to the unknown, to the next phase of spiritual evolution - Jupiter, the Temple of Love.