In Mark 9, Jesus heals a boy who has an unclean spirit inside of him. That's no small miracle in itself, but there's another amazing miracle displayed in this story; the mercy Jesus shows to the boy's father who cries out, "I believe; help my unbelief!" Christians are saved by grace through faith, but faith doesn't mean there are no more questions. There's mercy for believers who cry out to Jesus for help with their unbelief.