Now if we ask ourselves a little more closely, What is human nature? what are the characteristics by which men are distinguished from all other creatures? what is it which marks off our kind from every other kind, and which is always produced by human parents? we may find it hard to give a definition, but one or two things are obvious and indisputable. In the first place, we could not deny human nature to men who do not love God, or who even know nothing of Him. There are many whom we should naturally speak of as remarkably fine specimens of human nature, who yet never think of God, nor in any way acknowledge Him. It is plain, therefore, that the acknowledgment and love of God, which give us entrance into His kingdom, are _not_ a part of our nature, are not the gifts of our birth.
And yet is there anything that so distinctly separates us from the lower animals as our _capacity_ for God and for eternity? Is it not our capacity to respond to God's love, to enter into His purposes, to measure things by eternity, that is our real dignity? The capacity is there, even when unused; and it is this capacity which invests man and all his works with an interest and a value which attach to no other creature. Man's nature is capable of being born again, and that is its peculiarity; there is in man a dormant or dead capacity which nothing but contact with God, the touch of the Holy Ghost, can vivify and bring into actual exercise.
That there should be such a capacity, born as if dead, and needing to be quickened by a higher power before it can live and be of use, need not surprise us. Nature is full of examples of such capacities. All seeds are of this nature, dead until favouring circumstances and soil quicken them into life. In our own body there are similar capacities, capacities which may or may not be quickened into life. In the lower animal-creation many analogous capacities are found, which depend for their vivification on some external agency over which they have no control. The egg of a bird has in it the capacity to become a bird like the parent, but it remains a dead thing and will corrupt if the parent forsakes it. There are many of the summer insects which are twice-born, first of their insect parents, and then of the sun: if the frost comes in place of the sun, they die. The caterpillar has already a life of its own, with which, no doubt, it is well content, but enclosed in its nature as a creeping thing it has a capacity for becoming something different and higher. It may become a moth, or a butterfly; but in most the capacity is never developed, they die before they reach this end--their circumstances do not favour their development. These analogies show how common it is for capacities of life to lie dormant: how common a thing it is for a creature in one stage of its existence to have a capacity for passing into a higher stage, a capacity which can be developed only by some agency peculiarly adapted to it.
It is in this condition man is born of his human parents. He is born with a capacity for a higher life than that which he lives as an animal in this world. There is in him a capacity for becoming something different, better and higher than that which he actually is by his natural birth. He has a capacity which lies dormant or dead until the Holy Ghost comes and quickens it. There are many things, and great things, man can do without any further Divine assistance than that which is lodged for the whole race in the natural laws which make no distinction between godly and ungodly; there are many and great things man may do by virtue of his natural birth; but one thing he cannot do--he cannot quicken within himself the capacity to love God and to live for Him. For this there is needed an influence from without, the efficient touch of the Holy Spirit, the impartation of His life. The capacity to be a child of God is man's, but the development of this lies with God. Without the capacity a man is not a man, has not that which is most distinctive of human nature. Every man is born with that in him which the Spirit of God may quicken into Divine life. This is human nature; but when this capacity is so quickened, when the man has begun to live as a child of God, he has not lost his human nature, but has over and above become a partaker of the Divine nature. When the image of God, as well as of his earthly parents, becomes manifest in a man, then his human nature has received its utmost development,--he is born again.