Sanctification means that the Christians have been judged already, and that they are being preserved until the coming of Christ and are advancing towards it. All this has a threefold significance for the community of saints.

First, their sanctification will be maintained by their clearly separated from the world. 

Secondly, it will be maintained through their walking in a way which is worthy of the holiness of God.

Thirdly, their sanctification will be hidden, and they must wait for the day of Jesus Christ. 

Dietrich BonhoefferThe Cost of Discipleship1961 edition, 313-314).