It is "not too high a standard" to expect pastors to live free from sexual sin, says pastor John Piper.

Discussing purity in a recent "Ask Pastor John" podcast, the Desiring God founder said male pastors were mistaken if they think they are "just one of the guys". 

The podcast dealt with the question of whether "faultless chastity" is "too high a standard for pastors". 

The 'When I Don't Desire God' author made clear that in his view, this is exactly the standard pastors should be living to. 

He argued that as elders and pastors are in the roles of teachers and governors of God's flock, they are held to a higher standard of sexual purity than other Christians. 

"There are ethical standards where the pastor is to be above reproach (1 Timothy 3:2), because he's a very public figure and has the weighty calling of being an example to the flock (1 Peter 5:3) and an example to the world (1 Timothy 3:7)," Piper said.

Piper admitted it takes a "very special grace" to resist sexual temptation but added that this is achievable because God has made this grace available in Christ to all Christians. 

If pastors think that they are "just one of the guys", then this is "misplaced humility", the 74-year-old said. 

"They are the shepherd of the guys. They are the wolf-catchers and wolf-fighters of the guys," he said.

"They are examples to the guys. They are the protectors and teachers with authority over the guys.

"Maybe one of our problems is that we've just scared pastors witless about being what they ought to be."

He added that it is, in his view, "biblically inconceivable that such a shepherd could be living above the standard of Moses, and above the standard of ordinary Christians, and above the reproach of the world, and yet be living in sexual sin."

"My answer to the question is that it is not too high a standard to require that a pastor live a life free from sexual fornication and adultery and any ongoing use of pornography," he said.