Or, to put it another way...
Are you implying that there isn't a single amputee in this entire world with enough faith?
What I wanted to say that is a question of faith is that God answers prayers, even if it's to deny the request. After all, if God exists and have the attributes usually abscribed to Him (omniscience, omnipotence, omnipresence, and don't ask me how this can be possible, because I don't know either), can our limited minds undertansd His purpose? (gosh, what a load of mumbo-jumbo)