If you hold strongly to a belief that isn't true and have made up your mind never to compromise on that belief, it means you have become hardened.
This is a very risky mindset because that belief has become your form of defense from attacks, but it's not impenetrable. Truth can penetrate it, and once it's penetrated you may lose your life.
Be open minded if you aren't sure of your belief, so that once truth is known and verified, it becomes accepted, and you'll end up with an Impenetrable defense..
How to know the truth? Well, the simplest way to know for sure is to expose it to logic. Truth cannot be contradicted by any logic and you can defend it if you are well informed about it
