Far from bringing into Godhead, which is incommunicable as supreme, because we are creatures, I do not even accept a common expression from Romanists and others-union with God. But the moral elements of what He is God can communicate in giving us life in Christ. Nature is properly what makes any creature what it is, as "angel," "man," "cow," or anything else. 2 Peter 1:4 is not the simplest and clearest passage to explain the point, because it is properly moral, that is, specially what characterizes the Christian as such. The reason I think so is, that it speaks of great and precious promises, which to me mean what John 3 calls " born of water," and " ye are clean through the word which I have spoken unto you." Still it is not separable from the other point, life-giving. But it speaks of promises, and escaping corruptions which are in the world.
This truth of being born again, even Romanists, and also Armenians, and most evangelicals admit and confine themselves to, that is, an action of the Holy Ghost by the word by which man is morally purified. Nay, Wesleyans would say that it may be regained; and even those who do not go so far still hold it as only a purifying of what is. The Wesleyans say that man had body, soul, and spirit before the fall, and after the fall body, soul, and spirit corrupted; that, when one is born again, the corruption is removed; and hence that one may be quite perfect as man, if the corruption be wholly removed. But, without touching on perfection now, this is, to say the least, a most defective view of the matter. The Lord is a life-giving Spirit; and, operating by the Holy Ghost, " that which is born of the Spirit is spirit "-not the Spirit, who is God; but one is by His divine power quickened, just as that which is born of the flesh is flesh. I receive spiritually life from Christ, as I receive naturally life from Adam. In this sense Christ is my life. He is eternal life (1 John 1), and " he that hath the Son of God hath life." It is not I as of the flesh, but Christ lives in me.
Hence, viewed abstractedly as thus born (for so John views things), it is said he cannot sin, because he is born of God. And this life we have in the power of Christ's resurrection; and it is acted in by the Holy Ghost given to us because of Christ's work. So after His resurrection, as God breathed into Adam so Christ breathed into His disciples. Through this it is said, " the law of the Spirit of life in Christ Jesus hath made me free from the law of sin and death." A great accessory truth that comes in connected with this is, that, Christ having died, I am counted (Col. 3) of God dead as to the flesh, and am to count myself so (Rom. 6), and to realize it (2 Cor. 4), so that only the life of Christ should be manifested. This is the point to which my soul clings on the subject, the real communication of life in receiving Christ, by the power of the Holy Ghost acting in it in power, created again in Christ Jesus, though the flesh still be there. But I am not in flesh but in Spirit, and am privileged and bound to hold it dead. Of course, this does practically cleanse by and according to the word. One may not be able to explain it physiologically, but it is quite plain in Scripture; and in Spirit the saint will live eternally with God. "That which is born of the Spirit is spirit "-partakes of the nature of that of which it is born. It is holy, loves, and, as in Christ as a man, obeys. In a word it is the reproduction as to its nature of Christ's life. " If Christ be in you, the body is dead because of sin; the Spirit is life because of righteousness." It is as new a thing as a graft in a wild tree.
As regards using Old Testament facts as figures or types, our imagination is to be held in check, nor can we ever insist on such as doctrine. But there is a passage which may assist the mind on this point, 1 Corinthians 10:11, where the word " ensamples " is types or figures. This gives the principle. Then we must only look to the Holy Ghost and divine guidance to use them soberly and aright.
The shade of different meaning in koinonia and metekos is, I believe, just; but it is a question of adequate observation of its New Testament use in Greek, and any adequate proof would make one abandon it. Koinonoi is really partners in Luke 5, then, metekoi the fact of taking part; but I have no anxiety to insist on this.
Nature is moral in 2 Peter 1:4, from the force of what is said in the passage. In divine things this is everything, as holiness, love, etc.; but the point to be insisted on is, that there is more than mere moral effect, though there be this- that Christ is for us a life-giving Spirit; as born of flesh involves a like nature.
I do not know whether the question has been met as you wish, for there is no effort to anticipate and answer the objections easily made by unbelief. But I think, if you take the passages, the life-giving [quickening], and Christ being our life will be very plain; and that is what to my mind is so important, though we never know what it really means till we know it as deliverance in power, the flesh being held as dead, according to Rom. 8:2, 3, having passed out of the state described in chapter 7 according to the doctrine of chapter 6 and the beginning of chapter 7.