(P.40)...You should give your body exactly the number of hours of sleep that it needs; but your spirit should never be at sleep. Sleep, but see to it, that your spirit always remains active, even during the hours of sleep. There are so many people on earth who are unhappy, who suffer, who grope around in the dark: it is during the night in particular, that an Initiated person may come to their rescue.
His physical body is at rest, stretched out, unmoving, but his spirit is able to go everywhere, to bring help and light to all creatures. His spirit does not sleep, it remains active. You too can take up this work, on the condition that you learn to prepare for sleep.
Say to yourself, before going to sleep: "This night I am going to leave my body, to follow lessons in the invisible world, and to help people." Never forget to go to sleep with some splendid ideal to go and cooperate on the othger side, for it is thanks to this ideal, that you can give shape to your own future and that of all of humanity!
The book "The Power of Thought" can be supplied by Prosveta Nederland. Look at this site also for links to the English-language and other sites of the Brotherhood, that can supply books in your own language.