James and John corner Jesus to lobby for the prized position — seated at Jesus' right hand — once they join him in heaven. These guys have no idea what's going to happen to them.
Once they set out on their paths most of them will end up being killed (in very gruesome ways) rather than denounce their faith in Jesus. They will suffer higher highs and lower lows than anyone can imagine. They just don't get it yet.
The Christian faith teaches us that God is in and of sufferers not suffering. God turns to all of us in all of our need. God does not cause suffering. We do that without any help at all.