Tragically, moral failure is not uncommon among Christian leaders. The sins of high and low profile ministers have brought hurt upon many individuals and shame on the gospel and church. I personally have seen the effects sexual sin in particular can have on a congregation. Recently I was told that the secret to avoiding this caliber of moral failure is found in Galatians 5:16, where Paul writes,
In other words, walking in the Spirit everyday will keep you from giving into temptation. Conversely, human effort (i.e. "the flesh"), will set you up to fail
This is a fairly straight forward reading of the text, but I believe we run into a problem with the meaning we import into "walking in the Spirit". Typically, Evangelicals use this as short hand for reading the Bible, praying, and having an all around spiritual mindset. These are all things we can choose to do or not to do. Which means that the secret to avoiding mortal sin basically amounts to trying really hard. If you slip up once, you could be the next fallen leader sobbing on CNN.
If we're not careful, this subtle twist can simply have "walking in the Spirit" replace circumcision as the new law with which we try to justify ourselves, but clearly this isn't what Paul is talking about. Backing up to get some context we see in verse 5:
For through the Spirit, by faith, we ourselves eagerly wait for the hope of righteousness. For in Christ Jesus neither circumcision nor uncircumcision counts for anything, but only faith working through love.
In other words, it's faith that connects us to the hope of righteousness and the Spirit is means by which we believe and walk. Although spiritual disciplines are God's ordained means of sanctifying his people, it is believing the gospel that will keep us from gratifying the flesh.