The law of manifestation is the law of desire. That is, what becomes, comes into being because it wants to be. To understand how this might apply to human life, let us consider how it works in terms of the Absolute. The fifth-century Platonic teacher Proclus discussed the first manifestation of The One, which is the most fundamental reality, stepping into Being (which he calls the Noetic Absolute). At this level, Being is absolute and "unparticipated," or not yet manifested into form, but it represents an activated state that is stepped down from the undifferentiated absolute of The One. At this level, we're not even talking about God; God hasn't been born yet. This is something more mysterious even, like the unfathomable movements of the deep sea far below where we can see or sense.
Desire in human life is often seen as a mechanical principle. Drives for food and sex, for example, seem biologically programmed and the desires that spring from them are chemical impulses emanating predictably from a known configuration. But these biological life programs ultimately derive from the fundamental movements in the depth of Being when The One says, I want to be. Of course there is no I as we know it at that point. It's a movement of desire, though. And in all our human desires, that's really all we want too. To be, just like The One.
Ask yourself what you really want. Burrow deep into your desires and find the core question that always remains asking. You will never answer it. You will act, sometimes blindly, sometimes with consciousness, but never with complete success and fulfillment. It is in the nature of being to always begin again. And the ultimate mystery, that always hides itself in the final analysis, insures that the original desire that teases out the original condition of The One into the Seas of Noesis continuously breathes in us and through us.