Earlier in 1 Corinthians, Paul said that Christ has become our sanctification (1.30). He is the means by which we are made holy. The writer to the Hebrews says that Jesus is the one who made his people holy by the sacrifice of his body.
"And by that will, we have been made holy through the sacrifice of the body of Jesus Christ once for all." Heb 10:10, NIV. (See also Heb 2.11; 10.14,29; 13:12; Acts 20.32; 26.18; 1 Cor 1.2).
So we are to understand that sanctification results from the death of Christ, and benefits us when we become Christians. That is why we are called saints. God has set us apart from the rest of humanity, and has declared us to be holy. The idea is closely connected to justification. It describes the status we have in God's sight. He has included us in the group of people who are holy.
He has put us into that group despite our continuing sin. We are in the group of holy people because of God's grace, not because we are actually holy in practice. Christ has given his life so that we can be forgiven. Once we understand that sanctification is a gift from God, we are better able to understand why we should be holy in practice.
Sanctification has two parts. One is the gift from God which declares us to be holy and sets us apart into the group of people whom God regards as holy. The sequel is the holy behaviour which we are called to practise.
Dale
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