What do we mean when we say that we're "saved"? In Scripture, salvation concerns three realities: First, we have been saved. By his atoning death Christ secured our acceptance before God and when we placed our trust in Christ we were immediately justified and adopted. "There is therefore now no condemnation for those who are in Christ Jesus." But (second*) we are also being saved. At the same moment that the Holy Spirit creates faith by the preaching of the Gospel the believer is truly changed and his sanctification has already begun. Justification is a once-and-for-all declaration of right-standing because of an imputed righteousness; sanctification is a progressive growth in the grace and knowledge of our Lord Jesus Christ through an imparted righteousness. As living branches of the Savior's Vine, we immediately begin to bear the fruit of the Spirit, although others may be more aware of it than are we. Justification is instantaneous, objective and complete. Sanctification is progressive, subjective and partial. As the Heidelberg Catechism puts it, "For even the holiest of Christians make only a small beginning in obedience in this life. Nevertheless, they begin with serious purpose to conform not only to some, but to all the commandments of God." The Westminster Confessions adds, "Even our best works, as they are wrought by us, are defiled and mixed with so much weakness and imperfection that they cannot endure the severity of God's judgment." The question arises, then, why pursue good works at all? Why should we even be interested in sanctification? --Mike Horton, whole thing here

*The 3rd reality of salvation is that we SHALL be saved, on the Day of Judgment