Something goes awry in our thinking before sin becomes an action.  We embrace a kind of rationale that says, “This is okay, not so bad, and will not hurt anything or anybody.”  This is why the renewal of the mind (Rom 12:2) and having the mind of Christ (Phil 2:5) is so important to keep away from even the hint of sin.  We are admonished, “To abstain from the very appearance of evil.”  We also need to know that we are to abstain from the kind of thinking that leads to evil.

“For out of the heart come evil thoughts, murders, adulteries, fornications, thefts, false witness, slanders. These are the things which defile the man” Matthew 15:19-20a (NASB).