Q.77. Wherein do justification and sanctification differ? A. Although sanctification is inseparably joined with justification, yet they differ, in that God in justification imputes the righteousness of Christ; in sanctification His Spirit infuses grace, and enables the exercise thereof; in the former, sin is pardoned; in the other, it is subdued: the one does equally free all believers from the revenging wrath of God, and that perfectly in this life, that they never fall into condemnation; the other is neither equal in all, nor in this life perfect in any, but growing up to perfection.
So the first thing this tells us is that we must distinguish between the two, but never separate them. You cannot have one without the other (as they are “inseparably joined”), but they differ in significant ways. How, then, do they differ?
First, justification involves the imputation (or reckoning, accounting) of Christ’s righteousness, while sanctification involves the actual infusion of grace and the enabling to exercise it in daily life. You may recall that the Roman Catholic doctrine of justification mistakenly teaches that justification involves the infusion (rather than the imputation) of Christ’s righteousness. But the biblical doctrine of justification is that in Christ all believers are declared righteous, rather than made righteous. This is what Paul is speaking of in Romans 4:3-5,
“For what does the Scripture say? “Abraham believed God, and it was counted to him as righteousness.” Now to the one who works, his wages are not counted as a gift but as his due. And to the one who does not work but believes in him who justifies the ungodly, his faith is counted as righteousness . . . .”
Abraham was not justified by works, but by believing God at His Word in the promise of the gospel. Justification is (to borrow the words of v.5) a matter of God ‘justifying the ungodly’ (or the “wicked” – NIV), not matter of God making the ungodly person godly. (That would be sanctification.)
The second difference noted above in the Larger Catechism is that in justification sin is forgiven, while in sanctification it is subdued. In the former, all believers in Christ are forever freed from the just penalty of their sins – the wrath of God. But in the latter, the grace of God works in the lives of believers to subdue the power of sin over their lives. In other words, in justification we are viewed and accepted by God as sinless because we are in Christ; but in sanctification we begin to actually and objectively sin less than we did before coming to Christ by faith.
The third difference is a very important one, and that is that all believers are equally & perfectly justified, but sanctification can and does differ from one believer to the next in this life. There are no degrees of justification (i.e. you are either justified before God or you are not), but there most certainly are differing degrees of sanctification. Not only that, but while all believers are perfectly justified in this life, none of us are perfectly sanctified in this life. Not a one. In this life all believers are, by the grace of God, “growing up to perfection.”
So let us never separate justification and sanctification – they belong together. The one who has been once and for all time justified in Christ will also presently be in the process of being sanctified in this life. But let us also avoid the opposite mistake of confusing the two or mixing them up. To do that is to (at minimum) hinder our growth in grace, or even (at worst) to deny the gospel itself.