I stumbled upon this in John McLeod Campbell’s The Nature of the Atonement (1878):
[H]ow often have the points of agreement between the type and antitype been dwelt upon, as if to see that agreement was to understand the atonement, although the fullest recognition of that agreement leaves the questions still to be answered – Why must He who is to be the atoning sacrifice for sin, be Himself the Holy One of God? How does His being so qualify Him for bearing our sins? In what sense could they be, and have they been laid upon Him? Being laid upon Him, how is the shedding of His blood an atonement for them? How is His moral and spiritual perfection so connected with, and present in His bearing of men’s sins, and in His tasting death for every man, as that “we have redemption through His blood, even the forgiveness of sins,” because He, “through the eternal Spirit, offered Himself without spot to God?”
These questions are not answered by tracing the points of agreement between the type and the antitype, and therefore the seeming progress made in the understanding of the atonement by such tracing is altogether illusory.
Campbell sharply poses the question I’m tackling in my project: What is the relationship between biblical and systematic theology — between an interest in the grand narrative, longitudinal themes and typological correspondences in the Bible on the one hand, and a more philosophical, even ‘metaphysical’ concern with the ontological presuppositions of what has been fulfilled in Jesus on the other?
Suggestively (for my purposes anyway), it is precisely in relation to the person and work of Christ that Campbell finds biblical theology deficient — that is, exactly where we’d like it to carry us the furthest!