John Piper: Confounding Justification and Sanctification is deadly

John Piper explains the importance of the distinction between justification and sanctification:

It is not hard for a layperson to feel the preciousness of being counted righteous in Christ by faith alone. There are few sweeter words for a guilty sinner to hear. But the layperson may wonder if this apparent obscuring of the distinction between justification and sanctification really matters. It does. Our only hope of progress in gradual sanctification (growing in likeness to Jesus) is that we already have a right standing with God by faith alone. By this justification we are accepted into God’s favor and enjoy a reconciled position. This right standing establishes the very relationship in which we find the help and power to make progress in love.

This is the very structure of salvation in the book of Romans. Precisely because “those who receive the abundance of grace and the free gift of righteousness reign in life through the one man Jesus Christ” (Romans 5:17, ESV), it seems plausible to say, “Let us sin that grace may abound” (Romans 6:1). But Paul says, “No.” Then follows his great teaching on sanctification in Romans 6 and 7. And the foundation of it is that when we were united to Christ by faith (Romans 6:5), Christ’s death and righteousness became ours. We died with him, and righteousness was reckoned to us in this union. Now, and only now, can we successfully break free from our actual slavery to sinning. “We know that our old self was crucified with him in order that the body of sin might be brought to nothing, so that we would no longer be enslaved to sin” (Romans 6:6, ESV). A decisive death with Christ and bestowal of the “gift of righteousness” (5:17, ESV) has happened in union with Christ. Now we can joyfully and confidently fight to become what we are in Christ—free and righteous. “You also must consider yourselves dead to sin and alive to God in Christ Jesus” (Romans 6:11, ESV).

If the battle of sanctification is made part of our justification, as the newer challenge tends to make it, a great part of the foundation for triumphant warfare against sin is removed, and we are made to fight a battle that has already been fought for us and that we cannot win. Oh, there is a battle to be fought. And it is deadly. “If you live according to the flesh you will die, but if by the Spirit you put to death the deeds of the body, you will live” (Romans 8:13, ESV). “Be killing sin or [sin] will be killing you,” as John Owen says [Mortification of Sin in Believers, in The Works of John Owen, Vol. 6 (Edinburgh: The Banner of Truth Trust, 1967), p. 9.]. But what is distinctive about the Christian warfare is that we can only kill the sin that has already been killed when we were killed in Christ. Or, to put it positively, we can only achieve practical righteousness as a working out of imputed righteousness. The battle is to become what we are in Christ: righteous with the imputed righteousness of Christ.

Yes, it matters whether the declaration of justification and the liberation of sanctification are distinguished. The battle will be engaged differently without this faith, and the fallout cannot be a happy one over the long haul. (John Piper, Counted Righteous in Christ [p. 49])