Sanctification means “to be set apart, to be made holy.” It is the process by which believers yield to the Holy Spirit and allow Him to do His work in their lives, changing them from the inside out. Theologians have pointed to three phases of the one process of sanctification: the initial act of setting apart at salvation (positional); the ongoing process of becoming more and more set apart and Christlike (progressive); and the final setting apart from sin when believers are made perfect at the coming of Christ (perfected). First Thessalonians 3 and 4 include these three aspects:
(1) Positional Sanctification: I was sanctified— “For God did not call us to uncleanness, but in holiness” (4:7).
(2) Progressive Sanctification:I am being sanctified— “For this is the will of God, your sanctification” (4:3).
(3) Perfected Sanctification:I will be sanctified— “So that He may establish your hearts blameless in holiness before our God and Father at the coming of our Lord Jesus Christ with all the saints” (3:13).
*SOURCE: David Jeremiah Study Bible. Nashville, TN.: Worthy, 2013, p. 1687.