We are sanctified — set apart by God Himself, for Himself and according to His holiness.
When God rested on the seventh day, He sanctified (set apart) that day as a day of rest for Himself. He sanctified (set apart) an earthly people for Himself. He set apart a place among them where He, in holiness, could be with them. Whenever the priest was to come before Him, he was to sanctify himself to come near according to the holiness of God.
We have been sanctified for God through the cleansing blood of the Lord Jesus. Now we are to live practically according to God’s holiness. “Be ye holy, for I am holy.”
The world in which we live is a wicked, polluted, unholy place. The object of our hearts has set Himself in a holy place apart from all sin. We are instructed, “Set your affection [mind] on things above, not on things on the earth” (Col. 3:22Set your affection on things above, not on things on the earth. (Colossians 3:2)). When our minds are occupied with the Sanctified One, then our hearts and lives are separated from this evil world. When, as a result of such occupation, we separate ourselves from all that is not according to God’s holiness, we become sanctified vessels, clean and fit for the Master’s use.