Never leave or forsake you? who exactly does that apply to? what does it mean.?

does this verse say that i will never leave or forsake you unless you stop going to church? unless you start drinking beer occasionally? maybe smoke a cigarette? Unless you stop going to church ever time the doors are open? what does it mean. it sure seems like many people fall away for this statement to be true. Or are there other verses that are in a completely different part of the bible that compensate?