The Archbishop of Canterbury is challenging Christians around the world to follow up 10 days of prayer with action.
Hundreds of thousands of people across 85 countries took part in Justin Welby's 'Thy Kingdom Come' drive – the biggest prayer and evangelism push in a generation.
'I can hardly believe it,' he says in a new video.
'It's an extraordinary joining together of Christians all around the world to pray two prayers – "Thy Kingdom Come" and "Come Holy Spirit". Two prayers that are literally world changing.'
But he goes on: 'We have to say when we have prayed – what do we do now?
'How do we respond to the fact that when we pray God changes the world and God changes us? Our wills are aligned with God.
'What we want is brought more in tune with what he wants.'
Describing the 10 days of prayer between the Christian festivals of Ascension and Pentecost as an 'amazing' thing to have been involved in, he says: 'We have prayed "Thy Kingdom Come".
'So what are we going to do for us to be part of the answer to that prayer, in our families in our communities, in our homes, in our nations?
'What are we going to do, not so that people look at us and say "That's very special" but so they say "There is Christ's kingdom being seen"?
'It could be anything but it will be about meeting need and aligning our actions with the will of God.'
He goes on: 'What are you going to do in the most sensitive, generous loving way, in the way you would like to be treated, that enables them to have an opportunity to hear about Jesus Christ'?
He adds: 'Be sensitive, be loving, be full of the grace that God is showing to you and to me.
'But do something.'
He finishes: 'May God bless you as you change the world and in changing it you are changed by the Holy Spirit.'