Human beings are like submarines insofar as, inwardly, they carry devices that allow them to find their way in the invisible world

"Spiritual life should not be embarked upon rashly, because you can get lost in it just as much as you can get lost at sea without a compass. Although in spiritual life too you can have a compass. There are also other ways of finding your way even if you cannot see where you are going. What do the occupants of a submarine do to find their way around at the bottom of the sea? Nothing, but the submarine is equipped with devices giving out readings that the captain can interpret and so avoid accidents. Well, human beings are like submarines insofar as, inwardly, they carry devices that allow them to find their way in the invisible world. For the moment, however, these devices are covered in rust because they have not been used for incarnations, or they are broken because of the disordered life these human beings have led. So it is now up to them to put them back in working order."