5 This is the message we have heard from him and declare to you: God is light; in him there is no darkness at all. 6 If we claim to have fellowship with him yet walk in the darkness, we lie and do not live by the truth. 7 But if we walk in the light, as he is in the light, we have fellowship with one another, and the blood of Jesus, his Son, purifies us from all sin.
One of the hallmarks of a Redneck Jedi is to have your dad keep asking "C'mom over to the Dark Side, son, it'll be a hoot." Not really.
As the old saying goes, nothing good happens at a nightclub at 2AM, at least not much of anything that has lasting value. It's easy to try and explain away various vices, especially when you can play the legalist card to shut up anyone who wants to engage you on the issue.
However, such a split spiritual personality will tend to be fruitless and dead, which is what the author is trying to warn against.