Faith that there is a god who has abilities I not only don't understand but don't have the capacity to understand.
I am always fascinated at how important it is that we not be allowed to "understand" God. It's a helpful dodge since no one can agree on what God is really like (hence the zillions of different religions) so it's best if we just throw up our hands and say "I believe in something without evidence but that's because I can't possibly understand it so don't ask me to explain it!"
Once you accept your mortality faith comes easier and life become infinitely more rewarding.
Faith is usually based on fear of one's mortality. Facing mortality without the promise of an afterlife, that takes some skill. And it truly DOES make life more rewarding since we know this is the ONLY GO-ROUND we get on the wheel.