Imputation - An Union of Representation...

James Buchanan:

"Take the three cases of Imputation which have been specified, and

compare them with one another. We find, that in two out of the three, a change of moral character is the invariable concomitant or consequent of imputation; for the imputation of Adam’s guilt to his posterity, was connected with their loss of original righteousness and the corruption of their whole nature; and the imputation of Christ’s righteousness to His people is connected, in like manner, with their renewal and sanctification; but we also find that, in the third case, —which is as real and as complete an instance of imputation as either of the other two, —the imputation of our sins to Christ was not connected with any change in His holy character, or with the infusion of any, even the slightest’ taint of moral evil; whence we infer that imputation, so far from consisting in, is not even invariably connected with, the infusion of moral qualities. 

• We find again, that in two out of the three cases, representative, and personal, agency are so clearly distinguished as to make it manifest, that the party to whom anything is imputed is not supposed to have had any active participation in the doing of it: for our sins were really, and in the full sense of the term, imputed to Christ as our substitute, yet He had no share in the commission of them; and His righteousness is, in like manner, imputed to us for our Justification, yet we had no share with Him in ‘finishing the work which the Father had given Him to do.’ 

"—Whence we infer that, in the third case, —that of the imputation of Adam’s guilt to his posterity, —it is so far from being necessary to suppose our personal participation in his act, that such a supposition would go far to destroy the doctrine of Imputation altogether, by setting aside the fundamental distinction between the agency of the representative, and that of those who were represented by him. 

"We find, again, that in all the three cases, imputation, whether of sin or of righteousness, is founded on a federal relation subsisting between one and many, —for Adam was constituted the head and representative of his race, and Christ the substitute and surety of His people; and that this relation may be fitly described as amounting to a union between them, in virtue of which they are regarded and treated as being, in some respects, one; but that this union is not such as to destroy the distinction between their respective personalities, or to confound their several acts: for it is still true, that the representative was personally different from those whom he represented, and that his obedience, or disobedience, was his own act, and not theirs, although it is imputed to them; for ‘a union of representation is not a union of identity.’ ‘No imputation of this kind,’ says Dr. Owen, speaking of the imputation of anything that was not ours antecedently, but that becomes ours simply by being imputed, —‘is to account them, unto whom anything is imputed. to have done the things themselves which are imputed unto them… . This is contrary unto the nature of imputation, which proceeds on no such judgment, but on the contrary, (implies) that we ourselves have done nothing of what is imputed unto us, nor Christ anything of what is imputed unto Him.’"

James Buchanan. The Doctrine of Justification