109:5.4
The great problem of life is the adjustment of the ancestral tendencies of living to the demands of the spiritual urges initiated by the divine presence of the Mystery Monitor. While in the universe and superuniverse careers no man can serve two masters, in the life you now live on Urantia every man must perforce serve two masters. He must become adept in the art of a continuous human temporal compromise while he yields spiritual allegiance to but one master; and this is why so many falter and fail, grow weary and succumb to the stress of the evolutionary struggle.