Anthony Hoekema defines sanctification like this: “that gracious operation of the Holy Spirit, involving our responsible participation, by which He delivers us as justified sinners from the pollution of sin, renews our entire nature according to the image of God, and enables us to live lives that are pleasing to Him.” Or, more simply, the process that believers are made more like Jesus.
There are three aspects of sanctification.
Positional sanctification happens immediately at salvation, and is the washing and cleansing of the new believer where God sets him apart as his own. Paul writes of believers who were sanctified at a specific time in the past: “but you were washed, but you were sanctified, but you were justified…” (1 Cor. 6:11). When a person gets saved, he is considered positionally sanctified. He is a saint. He is holy.
Progressive sanctification happens after salvation and is the process by which the believer is transformed into the image of Christ. Romans 6:19b reads “so now present your members as slaves to righteousness, resulting in sanctification.” Believers are to strive for holiness “without which no one will see the Lord” (Heb. 12:14).
Permanent sanctification happens at glorification, when believers are finally “not able to sin.” This will only come when we die and go to be with the Lord. “When we see him, we will be like him” John says (1 Jn. 3:2), ;and Revelation 21 makes clear that all sin and struggle and pain will be eradicated. In that state of glorification, there will be no possibility of sin destroying anything.