The subject of spiritual union is the most important, the most profound, and yet the most blessed of any that is set forth in the sacred Scriptures; and yet, sad to say, there is hardly any which is now more generally neglected. The very expression “spiritual union” is unknown in most professing Christian circles, and even where it is employed it is given such a protracted meaning as to take in only a fragment of this precious truth.
A.W. Pink