Is sanctification a process or a one-time event?

 Question from a Reader:

Is sanctification a process or a one-time event?

Answer from Chelsea Dudley:

When we look at Scripture there is a sense in which we, as believers, have already been sanctified (Hebrews 10:10). But even more clear is that sanctification is a process (Hebrews 10:14). Looking at what God means by justification will help make clear what sanctification is. Justification is a one-time event that happens at salvation when God declares the repentant sinner righteous before Him. God takes away our sins and gives us Christ’s righteousness. When God justifies us, we are declared righteous, we are declared holy. Sanctification is becoming what we already are. Philippians 3:12 says, “Not that I have already obtained this or am already perfect, but I press on to make it my own, because Christ Jesus has made me his own.” Every honest believer will admit he/she still struggles with sin. Before God we are declared righteous and holy, that is how God sees us. But we still struggle with becoming righteous and holy. Sanctification is the process of becoming holy. It is the process of becoming who Christ has already declared us to be. It is the process of being transformed into His image (2 Cor. 3:18).

Sanctification is accomplished by the work of the Holy Spirit in our lives. When we strive to honor God with obedience, He uses our obedience to transform us into the image of Jesus and make us holy. It is not our works that make us holy, but the Spirit’s work through us. Sanctification is a lifelong process and we won’t be completely holy until Christ returns and redeems all things.

Below are some resources that will bring even more clarification:

This is an excellent audio message by John Piper about sanctification, http://www.desiringgod.org/interviews/the-gospel-and-sanctification-part-1

Here is a video of Randy talking about sinless perfectionism. Sinless perfectionism is the natural outcome of thinking sanctification is merely a one-time event. Randy also addresses sanctification in this video, http://www.epm.org/resources/2010/Jun/15/sinless-perfectionism-video/   

This is a short blog on the task of sanctification, http://www.epm.org/blog/2012/Jan/2/gift-and-task-sanctification