Shortly before his death on January 1, 1937, J. Gresham Machen dictated a final telegram to his friend and colleague, Professor John Murray. It was brief: "I'm so thankful for the active obedience of Christ. No hope without it."
Here is a good explanation of what Machen meant.
Comments
Yet Reformers like Luther, Calvin, and others, did not believe in Active Obedience, and they pointed to very powerful texts like 2 Corinthians 5:21, Romans 3:21-26, Romans 4:6-8, and Galatians 2:21, which all frame justification as a matter of the Cross alone and forgiveness, no "active obedience".
Christ's righteousness is seamless, his righteous life and atoning death being inseparable: "with the precious blood of Christ, like that of a lamb without blemish or spot." (1 Pet 1:19). His death would not be perfect and meritorious were he not blameless and unblemished in his (active) life and obedience before the Father. By virtue of our union with Christ are we not united to (and share in) all of Christ and his righteousness.
Yet you have raised a good question as to whether this theological distinction is valid. Will study more.