A rare letter from Bob Dylan in which he makes frequent references to his faith is being auctioned online and may be sold for more than $20,000.

Written on Park Plaza paper in April 1980 to a friend named 'Steve', the letter says Dylan is "up in Toronto singing and playing for about 3000 people a night in a downtown theatre".

Dylan goes on: "The Spirit of the Lord is calling people here in their beautiful and clean city but they are more interested in lining up for Apocalypse Now than to be baptized and filled with the Holy Ghost – Wanna thank you for that Bible as it is helpful in discovering a few phrases from and shedding more light on what the King James version reads – God will lift up your heart as you begin to realize that 'He thru Christ has reconsiled [sic] man unto Himself' (II Corinthians)."

Steve, he says, is in "basic training and boot camp and I thank God you are and your commitment runs deep and you will be used to minister and break the hold of darkness in those you become face to face with".

He encourages Steve to pray and press on, "Always in the name of Jesus Christ Son of God, Manifest in the flesh."

The letter has the original envelope and is described as being in "good to fine condition".

Dylan goes on: "The Spirit of the Lord is calling people here in their beautiful and clean city but they are more interested in lining up for Apocalypse Now than to be baptized and filled with the Holy Ghost – Wanna thank you for that Bible as it is helpful in discovering a few phrases from and shedding more light on what the King James version reads – God will lift up your heart as you begin to realize that 'He thru Christ has reconsiled [sic] man unto Himself' (II Corinthians)."

Steve, he says, is in "basic training and boot camp and I thank God you are and your commitment runs deep and you will be used to minister and break the hold of darkness in those you become face to face with".

He encourages Steve to pray and press on, "Always in the name of Jesus Christ Son of God, Manifest in the flesh."

The letter has the original envelope and is described as being in "good to fine condition".

The Toronto visit was for the legendary Massey Hall run as part of the Bob Dylan Gospel Tour after his conversion to Christianity. A year earlier he had produced his brilliant Slow Train Coming album, winning a Grammy award for the song 'Gotta serve somebody'. At Massey Hall he addressed crowds on the prophecies in Revelation, linking them to Russia's invasion of Afghanistan and an increasingly unstable Middle East.

Bidding at RR Auctions ends tomorrow, May 19.