“For this is the will of God, your sanctification: that you should abstain from sexual immorality; that each of you should know how to possess his own vessel in sanctification and honor, not in passion of lust, like the Gentiles who do not know God” (1 Thessalonians 4:3-5).
The word “sanctification” is a theological term that involves separation from sin and dedication to God. We can find a more precise description of this important doctrinal concept in the following definition: “the act or process by which people or things are cleansed and dedicated to God…” (1) One commentator expands on this idea with the following illustration…
“Just what does it mean to be sanctified? Suppose one were living in the time of Christ and wanted to make a gift to the temple. He would bring his gift of gold coins and lay them on the altar. What happened to those gold coins? The moment they were given to God they became sanctified. They were set apart for holy use. The sanctification did not change the character of the gold coins, but it did change their use and the purpose for which they were directed. So, every true Christian has been set apart as holy to God, even though he falls short of perfection.” (2)
In the New Testament, the concept of sanctification finds its foundation in Christ. For instance, Jesus made an important declaration concerning Himself as He spoke with the religious leaders of His day: “…why do you say that I’m dishonoring God because I said, ‘I’m the Son of God’? God set me apart for this holy purpose and has sent me into the world” (John 10:36 GW).
So just as Jesus was set apart for God’s purposes, those who are in Christ are set apart as well. The Biblical letter to the church at Ephesus offers a further illustration: “God chose us in Christ to be holy and blameless in God’s presence before the creation of the world” (Ephesians 1:3-4 NIV). In light of this, we can say that sanctification is a work of God through Christ.
However, it is also appropriate to add that every man and woman of God is involved in this process as well. We can revisit 1 Thessalonians 4:3-4 to illustrate this idea: “For this is the will of God— your sanctification: that you abstain from sexual immorality, that each of you learn how to maintain control over his own ‘vessel’ in holiness and honor” (Mounce, emphasis added).
This implies that God’s people are responsible to learn, grow, and participate in this ongoing process of sanctification, at least to some degree.
(1) New Dictionary of Theology, (Leicester/ Downers Grove: Inter-Varsity, 1988) pg. 613
(2) John F. Walvoord, The Rapture Question, pp. 34-35. Quoted in Notes on 1 Thessalonians 2020 Edition, Dr. Thomas L. Constable https://www.planobiblechapel.org/tcon/notes/html/nt/1thessalonians/1thessalonians.htm#_ftn131