Sanctification is the process by which the Holy Spirit makes us more like Christ in all that we do, think, and desire and increases our ability to repent from sin — by God’s grace, (1 Thess. 4:7; Eph. 2:10; 1 Tim. 4:4; 1 Peter. 3:15; 2 Tim. 2:25). This process continues all of the Christian’s life and is the result of salvation, not a cause of it, nor a contributing factor to it. Furthermore, the effort of sanctification does not maintain the believer’s salvation.

See also What is the difference between Justification and Sanctification?.