Man's Chief End

I like this summary of things:

The source of all man’s life is to be found in God. Through His strength and all-pervading power He maintains man’s growth and development and, as his ultimate goal, He constitutes that happiness which man of necessity pursues. Creator and goal, starting point and divine inspirer: this points to total dependence and asks for total devotion in return. Such a relation of dependence and devotion is the fundamental relationship between God and man. Man must acknowledge and express it, live by it inwardly and testify to it outwardly; for in this relationship is embodied his total human essence. He must completely surrender himself to God, and detach himself from everything which could impede that yielding. [A Handbook of the Catholic Faith, p. 304]