The special bus will end its week-long tour of central Scotland at the cenotaph, Paisley Cross with a Mass at 2pm.
The bus tour is the brainchild of the 'Friends of Divine Mercy Scotland'.
Organiser of the initiative, Helen Border said: "Inspired by the call from Pope Francis to 'Go out to the people and take the Church to them' we've decided to do just that, with a church on wheels."
The bus has visited Paisley, Coatbridge, Greenock, Barrhead and Glasgow during the week.
Bishop John said: "This is a fantastic initiative and a wonderful example of evangelisation, which takes the church out into the world.
"I hope this venture will be the first of many similar initiatives which offer people a route back to a relationship with God."
