Question: "What does it mean to be sanctified?"
Answer: To be sanctified is to be “set apart.” Synonyms for sanctified are holy, consecrated, and hallowed. The Bible speaks of things being “sanctified,” such as Mt. Sinai (Exodus 19:23) and gifts to the temple (Matthew 23:17); days, such as the Sabbath (Exodus 20:8); names, such as God’s (Matthew 6:9); and people, such as the Israelites (Leviticus 20:7–8) and Christians (Ephesians 5:26).
For a thing to be sanctified means it is set apart for a special use. Sinai was set apart from all other mountains for the giving of the Law. The temple in Jerusalem was set apart from all other locations for the worship of the one true God: “I have chosen and consecrated this temple so that my Name may be there forever. My eyes and my heart will always be there” (2 Chronicles 7:16).
Things that are sanctified are reserved for God’s purposes and should not be used for mundane tasks. The night Babylon fell, King Belshazzar “gave orders to bring in the gold and silver goblets . . . from the temple in Jerusalem, so that the king and his nobles, his wives and his concubines might drink from them” (Daniel 5:2). It was one of Belshazzar’s final acts, for he was killed that night by the invading Persians. God’s name is “hallowed” (Luke 11:2) and any flippant or disrespectful use of His name is profane.
Jesus spoke of Himself as being sanctified in John 17:19; in other words, He is holy and “set apart” from sin. His followers are to be similarly set apart from sin and for God’s use (see 1 Peter 1:16).
People who are sanctified are born again and therefore part of God’s family (Hebrews 2:11). They are reserved for God’s use. They know “the sanctifying work of the Spirit” in their lives (1 Peter 1:2). They abstain from sexual immorality (1 Thessalonians 4:3). They understand they have been “called to be his holy people” (1 Corinthians 1:2).
To be sanctified means that God has been at work in our lives. Under the Old Testament Law, the blood of a sacrifice was required to set things apart unto God: “In fact, the law requires that nearly everything be cleansed with blood” (Hebrews 9:22). Blood was sprinkled on tabernacle furniture, on priestly clothing, and on people. Nothing was considered sanctified until it had come in contact with the blood. This was a picture of the spiritual application of Christ’s blood for our salvation—we are “sprinkled with his blood” (1 Peter 1:2). Just as the temple of old was sanctified for God’s use, our bodies, temples of the Holy Spirit, are set apart for God’s holy purposes (1 Corinthians 6:19).
To be sanctified means that God’s Word has had an effect on us. It is “through the word” that God cleanses us and makes us holy (Ephesians 5:26; John 17:17).
God invites us sinners to come to Him “just as we are” and receive His mercy and forgiveness. When we are saved, the Holy Spirit begins His amazing work of transforming us into the image and likeness of Christ. To be sanctified means that God loves us too much to let us stay the same.
The apostle’s prayer is for all believers, everywhere: “May God himself, the God of peace, sanctify you through and through. May your whole spirit, soul and body be kept blameless at the coming of our Lord Jesus Christ” (1 Thessalonians 5:23).