Revelations 3:16
16 So then because thou art lukewarm, and neither cold nor hot, I will spue thee out of my mouth.
This is simple. There is no in between with God. He does not want someone who on Sundays serves him, but then on Monday lives a life of sin. However, so many people live this way. They need to realize that people watch this. They see you straddling the fence. You are going to hit a low spot and you will have to choose a side. It is simple, I would rather be on fire for God than be the one people wonder if I am christian.