It's an old magical principle - it's even filtered down into RPG systems - that magic, while taking a lot of effort, can be 'stored' - in a staff, for example. No doubt a wizard spends a little time each day charging up his staff, although you go blind if you do it too much, of course.
Terry PratchettClassically, very few people have considered that cleanliness is next to godliness. A rank loincloth and hair in an advanced state of matted entanglement have generally been the badges of office of prophets whose injunction to disdain earthly things starts with soap.
Terry PratchettNight poured over the desert. It came suddenly, in purple. In the clear air, the stars drilled down out of the sky, reminding any thoughtful watcher that it is in the deserts and high places that religions are generated. When men see nothing but bottomless infinity over their heads they have always had a driving and desperate urge to find someone to put in the way.
Terry Pratchett