Because you can’t know everything first-hand. You can’t experience everything. You can’t go everywhere. Or see everything. Or hear everything. Or touch everything. Or taste everything.
You can’t talk to everyone. Or read every book. Or attend every class. Or listen to every podcast. Or watch every documentary.
I’ve never been to Paris, but I believe that it’s beautiful.
I’ve never skied, but I believe that it’s fun.
I’ve never had cancer, but I believe that chemo can kill it.
I’ve never tasted the Carolina Reaper, but I believe that it’s hella hot.
I’ve never climbed Everest, but I believe that it feels triumphant.
I’ve never heard the voice of God, but I believe that it’s kind.
At some point you have to accept that faith is always, to some degree, second-hand. At some point you’re going to have to take someone’s word for something.