Sanctification is another one of these long, theological words. Let’s break it down. To sanctify is directly related in the original biblical languages to the word for “holy.” So, “to sanctify” means “to make holy.” The English word sanctify is related to the word saint. Sanctification is the process of making something saintly, or holy.
Therefore Jesus also, that He might sanctify the people with His own blood, suffered outside the gate. (Hebrews 13:12)
Jesus went outside the city as a sin offering. (See, for example, John 19:16–20.) We learn from the Old Testament that sin offerings could not be offered within the compound of God’s people. (See, for example, Exodus 29:14.) Sanctification always includes separation.
To make ourselves holy, we must offer the right testimony: “Through the blood of Jesus, I am sanctified, made holy, set apart to God, separated from all that is evil. Between all evil and me is the blood of Jesus.”
The one who is sanctified is in an area where God has access to him, but the devil does not. To be sanctified is to be removed from the area of Satan’s visitation and reach and to be placed in an area where we are available to God, but not at home when the devil calls. That is what it is to be sanctified, made holy, set apart to God.