R.J. Rushdoony: Justification is by imputation, an act of God from beginning to end

“Biblical justification is by imputation. Although man is not righteous before God, God the Judge imputes the righteousness of Jesus Christ to the sinner and declares him justified. As Berkhof wrote, ‘Justification is a judicial act of God, in which He declares, on the basis of the righteousness of Jesus Christ, that all the claims of the law are satisfied with respect to the sinner.’ From beginning to end, justification is the act of God: He is the lawgiver whose law has been broken. He is the court and Judge before whom all flesh shall appear. He is the Redeemer whose atonement affects man’s justification. And, before all this He is the Creator, who made all things, including man.” (R.J. Rushdoony, "Systematic Theology," p. 631)