Theologically the separation from the Eternal Life is said to be caused by "Sin." But what do we mean by "Sin"?
We can only judge of what a thing _is_ by what it _does_; and so, if "Sin" is that which prevents the inflowing of the Eternal Life, which we know is the root of our individual being, then it must be the transgression of the inherent Law of our own Being. The truth is that we live simultaneously in two worlds, the visible and the invisible, just as trees draw their life from the earth beneath and from the air and light above, and the transgression consists in limiting ourselves only to the lower world, and thereby cutting ourselves off from the essential part of our own life, that which _really lives_.
We do not realize the true function of the three lower principles of our nature, viz.: Vital Spirit, etheric body, and outward form; the function of which is to give concentration to the current of spiritual life flowing from the Eternal Spirit, and thus enable the undifferentiated Life to differentiate itself into Individual Consciousness, which will be able to specialize the action of the Law into higher manifestations than it can produce without the co-operation of Personality.
On the analogy of Ohm's Law our error is making our "_R_" so rigid that it ceases to be a conductor, and so no current is delivered and no work done. This is the true nature of sin, and it is this opposition of our _R_ to E.M.F. or Eternal Motive Force that has to be removed. We have to realize the true function of our R, as the channel through which the E.M.F. is enabled to carry on its work. When we awake to the fact that our true place in the Order of the Universe is to be fellow-workers with God in carrying on the work of Creation, then we see that hitherto we have entirely missed the purpose of our calling, and have misused the Divine image in which we were created; and therefore we want an assurance that our past errors will not stand in the way of our future advance into continually fuller participation in the Divine Creative Work, which, in virtue of our true nature should be our rightful inheritance.
That our future destiny is to actually take an individual part, however small, in guiding the great work of Evolution, may not be evident to us in the earlier stages of our awakening; but what is clear as a matter of feeling, but not yet intellectually, is, that in some way or other we have been cutting ourselves off from the Great Source of Light, and that what we therefore want, is to be re-united to it. What is wanted, then, is something which will give us a firm ground of assurance that we _are_ re-united to it, and that that something must be of such a nature as never to lose anything of its efficiency at any stage of our progress--it must cover the whole ground.