Quoting you, “The best defense is to know what you believe and why, and be able to articulate it when confronted with these attacks.” While I don’t believe I’m all that articulate, I do know what I believe but I don’t know the answer to “why” I believe – I just believe. What is the answer?
Knowing why you believe means you know what the Bible says well enough to be able to use it to justify your belief. That way if someone challenges your belief you can support it with Scripture.
For example, I get numerous letters from pre-trib believers who ask for help when confronted by people who are not pre-trib. By their questions I can tell they’ve never done enough study to know why the pre-trib view is correct. What would be a simple question for someone who has done a little studying stumps them. Because of this, seeds of doubt are planted in their minds and they’re no longer as certain about it as before.
Fortunately, knowing the timing of the rapture is not essential to our salvation. But I also get a lot of questions about things that are essential. It’s my opinion that many in our generation of Christians are guilty of having zeal without knowledge (Romans 10:2). They know what they believe but since they can’t back it up with Scripture, they don’t know why they believe it. If they’re ever asked to defend their beliefs they quickly discover they can’t do it.