Faith keeps you going when belief starts to wane.
You know that feeling you get when you’re super-energized and everything feels right with the world and your relationship with God? It’s the whole reason you became a Christian, pored for hours over the Bible trying to study it. Well, in my case it was a ton of other spiritual texts, just now getting into the Bible, but hey.
Well, they don’t last forever. It’s got much less to do with God and a lot to do with how your brain works. Peak experiences use up a lot of mental energy, dopamine, all of that. It runs out, but you’re still left with a high from the experience. Eventually that fades too, and you’re left in a low point. Belief is more than this, but it’s this that I’m going to call belief for the purposes of this discussion.
Once your spiritual high has run its course, faith takes over and starts priming you for another peak experience. Everybody experiences it somewhat differently. If you looked at my life, you’d be forgiven for thinking I’d fallen into some kind of deep depression. But I’m not, I really prize extremely low-energy states. They’re where I’m at my most mystical.
Faith is how times in your life which aren’t amazing and high can be transformed into a worthwhile and fun experience anyway. You know God’s there and the low point gives you the opportunity to look for Him in places you hadn’t before considered to look. This is also why doing regular prayer is important, they keep you connected to God. Just going through the motions is helpful the same way training is. You want to turn to God first, not last, and without regular practice you won’t think to do that when it counts.