The spiritual body, which is reserved for spiritual men, is a body in which the upholding life is spiritual. The natural life of man both forms to a human shape and upholds the natural body; the spiritual body is similarly maintained by what is spiritual in man. It is the soul, or natural life, of man which gives the body its appetites and maintains it in efficiency; remove this soul, and the body is mere dead matter. In like manner it is the spirit which maintains the spiritual body; and by the spirit is meant that in man which can delight in God and in goodness. The body we now have is miserable and useless or happy and serviceable in proportion to its animal vitality, in proportion to its power to assimilate to itself the nutriment this physical world supplies. The spiritual body will be healthy or sickly in proportion to the spiritual vitality that animates it; that is to say, in proportion to the power of the individual spirit to delight in God and find its life in Him and in what He lives for.
We have already seen that Paul refuses to consider the resurrection of Christ as miraculous in the sense of its being unique or abnormal; on the contrary, he considers resurrection to be an essential step in normal human development, and therefore experienced by Christ. And now he enunciates the great principle or law which governs not only this fact of resurrection, but the whole evolution of God's works: "first that which is natural, afterward that which is spiritual." It is this law which we see ruling the history of creation and the history of man. The spiritual is the culminating point towards which all the processes of nature tend. The gradual development of what is spiritual, of will, of love, of moral excellence--this, so far as man can see, is the end towards which all nature constantly and steadily is working.
Sometimes, however, it occurs to one to question the law "first that which is natural, afterward that which is spiritual." If the present body hinders rather than helps the growth of the spirit, if at last all Christians are to have a spiritual body, why might we not have had this body to begin with? What need of this mysterious process of passing from life to life and from body to body? If it is true that we are here only for a few years and in the future life for ever, why should we be here at all? Why might we not at birth have been ushered into our eternal state? The answer is obvious. We are not at once introduced into our eternal condition because we are moral creatures, free to choose for ourselves, and who cannot enter an eternal state save by choice of our own: first that which is natural, first that which is animal, first a life in which we have abundant opportunity to test what appears good and are free to make our choice; then that which is spiritual, because the spiritual can only be a thing of choice, a thing of the will. There is no spiritual life or spiritual birth save by the will. Men can become spiritual only by choosing to be so. Involuntary, compulsory, necessitated, natural spirituality is, so far as man is concerned, a contradiction in terms.
Human nature is a thing of immense possibilities and range. On the one side it is akin to the lower animals, to the physical world and all that is in it, high and low; on the other side it is akin to the highest of all spiritual existences, even to God Himself. At present we are in a world admirably adapted for our probation and discipline, a world in which, in point of fact, every man does attach himself to the lower or to the higher, to the present or to the eternal, to the natural or to the spiritual. And although the results of this may not be apparent in average cases, yet in extreme cases the results of human choice are obtrusively apparent. Let a man give himself unrestrainedly and exclusively to animal life in its grosser forms, and the body itself soon begins to suffer. You can see the process of physical deterioration going on, deepening in misery, until death comes. But what follows death? Can one promise himself or another a future body which shall be exempt from the pains which unrepented sin has introduced? Are those who have by their vice committed a slow suicide to be clothed hereafter in an incorruptible and efficient body? It seems wholly contrary to reason to suppose so. And how can their probation be continued if the very circumstance which makes this life so thorough a probation to us all--the circumstance of our being clothed with a body--is absent? The truth is, there is no subject on which more darkness hangs or on which Scripture preserves so ominous a silence as the future of the body of those who in this life have not chosen God and things spiritual as their life.