Atheist/theist behaviour

[Neo-Scholastic]

Atheist: No ones' watching and what's the harm anyway?
Theist: It will distance me from the things I most value.

What is this supposed to mean please? 

Are you saying some theists put value on not doing certain things even if they cause no harm?

All people naturally tend to rationalize small compromises of conscience. For example, if a teller rings up the wrong price for a small item like a pair of socks and not correcting the total. Or taking the unused shampoos or soaps from the hotel room. Or letting one’s gaze linger on some exposed cleavage. If people evaluate their actions according to the most common secular value systems, it is fairly easy to justify such actions: Wal-Mart can absorb the cost of the teller’s mistake; the maids would throw out the soaps anyway, it’s okay to just look, etc. Thus in absence of moral absolutes a person’s character is susceptible to slow corrosion. Eventually, people start to compromise on bigger issues like murdering unborn babies. This kind of corruption is also possible in more abstract theistic moral systems wherein one hopes to gain the mercy and favor of God/gods by having a positive balance in the ledger of good versus bad deeds. Christian morality is a little bit different because it is based on a personal relationship with our Lord and Savior. Such constant communion drives believers to think and act in ways that will bring closer union with the Lord. That is why David said, “Against Thee alone have I sinned.”