How do we mortify sin?

“The first thing to do is: Turn to the Scriptures. Yes, turn to John Owen (never a bad idea!), or to some other counselor dead or alive. But remember that we have not been left only to good human resources in this area. We need to be taught from ‘the mouth of God’ so that the principles we are learning to apply carry with them both the authority of God and the promise of God to make them work.” - Ligonier