“In Latgalia [a region of Latvia] they say, 'Oh, as soon as the missionaries left, we all just jumped in the river and washed it off, anyway.'” (Sean McLaughlin)
It's the first of the traditional Three Questions asked by the Horned at an initiation (and later repeated during the Renewal of Vows):
Do you renounce the waters of baptism?
Old Craft initiations are very different from Wiccan ones. They're not secret at all. Those who wish to take the Oath must first know the Oath. How can you swear to something that you haven't had the chance to think through thoroughly? You need to know what you're letting yourself in for. One cannot join the Tribe of Witches all unwitting.