The Lord Jesus Christ was not only an equal member in the Godhead before His incarnation, but He retained that reality in “the days of His flesh.” But the experience of the incarnation by which two [lives] natures are united in one Person belongs only to the Son.
The Father and the Spirit are seen to be associated and active in all that concerns the Son; but it was the Son alone who took upon Him the human form and who is, therefore, through glorification, a Kinsman in the human family. And as complex and difficult as it may be to our human minds, the original Trinitarian unity abides as perfectly after the incarnation as before (cf. John 10:30; 14:9, 11).
By means of the incarnation the Lord Jesus assumed a complete and perfect humanity. This He did not possess before, and its addition to His eternal Deity has resulted in the God-man which He is. Though His Deity is eternal, the humanity was gained in time. Therefore, the theanthropic Person — destined to be such forever — began with the incarnation.
It is also revealed that though the assumption of His humanity was first a condescension and afterwards a humiliation, through His death, resurrection, and ascension He acquired a surpassing glory. There was a joy which was “set before Him” (Heb. 12:2), and, because of the obedience manifested in the Cross, God “hath highly exalted Him” (Phil. 2:9). Reference is thus made to a glory and joy exceeding every glory and joy that had been His before.
A glorified man whose humanity has not been renounced is in heaven. As such He ministers on behalf of His own who are in the world, and as such He is seated upon the Father’s throne expecting until, by the authority and power of the Father committed unto Him, His enemies shall be made the footstool of His feet (Heb. 10:12, 13), and the kingdoms of this world are become “the kingdoms of our Lord, and of His Christ” (Rev. 11:15). Therefore, it is to be recognized that the theanthropic Person is very God and very man, and that His humanity, perfect and complete, is as enduring as is His Deity.
The truth that is so evidently taught in the New Testament is that undiminshed Deity — none other than the second Person, whom He eternally is — incorporated into His Being that perfect humanity which He acquired and ever will retain. Of these two [lives] natures it may be affirmed from the evidence which Scripture provides, that they united in one Person, and not two; that in this union, that which is divine is in no way degraded by its amalgamation with that which is human; and, in the same manner and completeness, that which is human is in no way exalted or aggrandized above that which is unfallen humanity.
It is only natural to suppose that the divine nature would be injured to some extent if combined with that which is human, and the human nature would be exalted out of its precise limitations if combined with the divine. The teaching of the Scriptures serves to save us from such natural conclusions. The Deity of the Lord Jesus Christ is unimpaired by its union in the one Person with that which is unfallen human nature, and the unfallen humanity retains its normal limitations. The confusion and uncertainty that would follow if these [lives] natures were subject to problematical alterations is beyond estimation.
— L. S. Chafer
Miles J. Stanford. (2002;2002). Complete Works of Miles J. Stanford. Galaxie Software.