My personal belief is bad things happen for a reason. God allows Satan to harm us to provide challenge, and testimony for greater good.
for example: Jesus.
He was a perfect human. he did no
wrong, and yet he suffered his whole life. He doesn't know why he has to die, in fact he cries out to God after being on the cross for nine hours “My God, my God, why have you forsaken me?”
yet his death was used for the greatest purpose of all, the promise of eternal life for all true believers.