The Shaw Pocket Bible Handbook, Walter A. Elwell, Editor, (Harold Shaw Publ., Wheaton , IL; 1984), pp. 357-358
The process of developing holiness. God said to Israel, "Be holy, because I am holy" (Lev. 11:44-45>). Because God wants us to become like him, it is necessary that his people be a special kind of people, holy men and women. The basic idea in sanctification is "being set apart for God"; those thus set apart live in a way that is pleasing to God. They have no power of their own to do that, but God enables them (2 Cor. 3:17-18>). Sanctification is not an option. God requires it of all his people (1 Thess. 4:3>).