St. Michael and Lucifer

Glorious St. Michael! prince of the heavenly host, protector of the universal Church, defend us against all our enemies, visible and invisible; do not permit that we should ever fall under their tyranny.
Most noble archangels! deign to direct and conduct us amidst the quicksands by which we are everywhere surrounded.

--Manual of the Children of Mary

If I ever get the chance to walk to Mont St. Michel, I think that prayer will be very useful, especially the last part.