Already you are clean because of the word that I have spoken to you” (John 15:3).
Sanctification is the work of God’s free grace, whereby we are renewed in the whole man after the image of God, and are enabled more and more to die unto sin, and live unto righteousness (Westminster Shorter Catechism, Q.35).
When we come to faith in Christ, putting our trust in him for salvation, we are expected to grow: “Regeneration is birth, sanctification is growth.”¹ The Scriptures at many places speaks of this. The apostle Peter, for example, says, “Like newborn infants, long for the pure spiritual milk, that by it you may grow up into salvation” (1 Peter 2:2).
One sure sign you are saved and growing in the faith is a desire for the word of God. Where this is absent, be afraid; you may not have experienced salvation yet. The apostle continues in the next verse, “if indeed you have tasted that the Lord is good.” (v.3). Have you tasted the Lord is good? Have you been saved? Then this should manifest in your desire for God’s word.
God’s word is how we grow and mature in the faith. It is how we are sanctified: cleansed and washed. Jesus in John 15 taught his disciples a lesson about sanctification: bearing fruit. He assures the disciples before he plunges in: “Already you are clean”. The understanding is that fruit-bearing is not required of them to be sanctified. But fruit-bearing is required of them because they are sanctified.
Fruit-bearing, therefore, is not antecedent to sanctification. Instead, sanctification is antecedent to fruit-bearing. We bear fruits because we are sanctified. And this work of sanctification takes place in our lives by God’s work of grace in the word. How are they already clean? Because of the words Christ spoke to them. To the Father, Jesus prayed: “Sanctify them in the truth; your word is truth.” (John 17:17). In sanctification, God washes us from sins and sets us apart for holy use, which we must walk in (1 Corinthians 6:11; Ephesians 2:10). Sanctification is an ongoing process where we are being formed to conform to the image of Christ.
1. J.I. Packer, Concise Theology: A Guide To Historic Christian Beliefs (Illinois: Tyndale House, 1993), 170