You may hear religious person say something like "you just have to have faith" when discussing religious topics, God, etc.
You know, as do I, that you don't HAVE to have Faith. Most of us - beliebers* included - instinctively understand this and operate accordingly. We use faith as a last resort, like when we jump off a cliff into a creek. We don't KNOW that there're no rocks immediately beneath the water's surface forty feet below, but we hope there aren't. Faith, in this instance, still isn't as good as knowing, but sometimes an epistemic shortcut is what we use, practical or not.
* don't ask me why Justin Bieber is relevant here. I just don't know.