We are made holy by his making himself holy and then we are called to be holy. So that the holiness of Jesus and the holiness of the church is something a great deal more than being ‘good’ or ‘virtuous’; it is being in the place where God through Christ makes peace between earth and heaven. It is being under the cross, in short. For a Christian to be holy is to be under the cross. A person may lead a deeply impressive moral life; they may even have a deeply impressive spiritual life, and yet if they don’t ‘live under the cross’, we can’t call them holy, in the biblical sense; and that living under the cross I first of all am acknowledging the unique and unrepeatable debt that we owe to the grace of God in the death of Jesus, living in gratitude for the gift given by Christ’s death and it is the seeking, day by day, to let that Cross live and work in us as we carry the cross in putting away our self-defending, self-justifying, self-protecting habits in every area of our lives. Holiness is living under the cross, the place where Jesus makes himself holy, so that we may be made Holy. It has all been done for us in the cross; God be praised; it is all, for each one of us to discover, day after day, in that self-emptying, that self-forgetting struggle to let Jesus live in us. No-one else, no other power, no other spirit.
Rowan Williams, One Holy Catholic and Apostolic Church.