Warfield on Imputation
In a 1909 entry on “Imputation,” written for the New Schaff-Herzog Encyclopedia of Religious Knowledge, in the second of six sections, Warfield defines the three acts inherent in a proper understanding of the meaning of “imputation.”
II. THREE ACTS OF IMPUTATION
From the time of Augustine (early fifth century), at least, the term “imputation” is found firmly fixed in theological terminology in this sense. But the applications and relations of the doctrine expressed by it were thoroughly worked out only in the discussions which accompanied and succeeded the Reformation. In the developed theology thus brought into the possession of the Church, three several acts of imputation were established and expounded. These are . . .
the imputation of Adam’s sin to his posterity;
the imputation of the sins of His people to the Redeemer;
the imputation of the righteousness of Christ to His people.
Though, of course, with more or less purity of conception and precision of application, these three great doctrines became the property of the whole Church, and found a place in the classical theology of the Roman, Lutheran, and Reformed alike. In the proper understanding of the conception, it is important to bear in mind that the divine act called “imputation” is in itself precisely the same in each of the three great transactions into which it enters as a constituent part. The grounds on which it proceeds may differ; the things imputed may be different; and the consequent treatment of the person or persons to which the imputation is made may and will differ as the things imputed to them differ. But in each and every case alike imputation itself is simply the act of setting to one’s account; and the act of setting to one’s account is in itself the same act whether the thing set to his account stands on the credit or debit side of the account, and whatever may be the ground in equity on which it is set to his account.
That the sin of Adam was so set to the account of his descendants that they have actually shared in the penalty which was threatened to it; and that the sins of His people were so set to the account of our Lord that He bore them in His own body on the tree, and His merits are so set to their account that by His stripes they are healed, the entirety of historical orthodox Christianity unites in affirming.
The essay can be found in its entirety here: B. B. Warfield: "Imputation"