An ancient Buddhist scripture which was preserved for the better part, by the oral tradition.. the Jataka tales are imbued with magick.
Superficially, it looks like a collection of children’s moral stories told mostly in the guise of the animal kingdom. However, on deeper inspection, one finds that each story is, in fact, a spell given in a riddle.
Sometimes, to add a bit of humour, the spell is literally mentioned somewhere in the story. For instance, there is the story of a priest who knew how to make gemstones shower from the sky.
So you see? The obstacle would be not only in believing such a thing but also the sheer complexity of it being such that it need not be guarded as a secret.