Is sanctification (the making of our holiness) a work of God or is it our own effort of obeying God’s commands? The bible teaches that it’s both. Though, it’s easy to over-emphasis one or the other. Today I’ll just say something about the work of God.
Sanctification requires an inward and supernatural change that God gives graciously to those who have faith in Christ. Charles Hodge says:
Sanctification in its essential nature is not holy acts, but such a change in the state of the soul, that sinful acts become more infrequent, and holy acts more and more habitual and controlling. This view alone is consistent with the Scriptural representations, and with the account given in the Bible of the way in which this radical change of character is carried on and consummated.
To illustrate, he says:
It is the making the tree good, in order that the fruit may be good. It involves an essential change of character.
Therefore, sanctification is not merely changing your actions, but taking on and depending on a new nature. If all you did was change your outward actions, it would be like taking colorful fake plastic fruit and attaching it to a dying tree. The fruit is counterfeit and of no real value. That’s not a picture of sanctification. The tree needs new life if it is to produce good fruit.
Sanctification must come from an inward change and an inward change can only come from the supernatural power and grace of God.
for it is God who works in you, both to will and to work for his good pleasure. –Philippians 2:13