My religion teaches me that they best way to live is by loving your neighbor as yourself. How can you prove if that is true or not? You cannot. All you can do is have faith it is true or not.
Actually, it's been pretty conclusively demonstrated that enlightened self-interest (doing good to the others with the expectation that good will be done back to you at some later point) is one of the best ways to live. It has nothing to do with religious beliefs, though. Simply put, the [wiki]norm of reciprocity[/wiki] (often called the rule of reciprocity).
Let's compare that with another statement of yours.
The Bible teaches that backsliden worshipers of Jehovah are a danger to my spirtuality. As such, they should be treated accordingly.
You're essentially arguing that if someone becomes a worshiper of Jehovah, and then later stops being a worshiper of Jehovah, that they're a danger to you and should be treated accordingly. However, I doubt you would have any problems with the idea of converting a Muslim to belief in Jehovah, even though the Muslims have a religious law which states that apostates (those who turn away from a religion) should be put to death. This is essentially a double-standard. It violates the rule of reciprocity - you are essentially arguing that people who convert away from your religion should be treated badly even while you imply that people who convert from another religion to yours should be exempt from similar rules on the part of their former religion.
Furthermore, the basis of this argument is that apostates are a danger to your 'spirituality'. Except, that begs the question of just what 'spirituality' is. Can you demonstrate what it is, or is it one of those things you just have to have faith about? Because if it's the latter, this is precisely what I was talking about
- a claim that you can't demonstrate or prove, and that leads you to declare that a certain category of people are a danger to you, thus leading to you treating them accordingly. In other words, based on a claim that you can't support, you're arguing that these people pose a danger to you and are claiming the right to act accordingly, which has the definite potential to be harmful. to others.