Is this the greatest philosophical quote of all time?
"Angels fly because they take themselves lightly; devils fall because of their gravity" - G.K.Chesterton
More completely it is:
"Angels can fly because they take themselves lightly. Never forget that the devil fell by force of gravity. He who has the faith has the fun." - G.K.Chesterton
It is a great quote to enforce how being being not serious, is the right way. To much gravitas and you fall to earth (or into hell) like a devil. Being un-serious (shame there is not a good word in English for un-serious) / taking yourself lightly, allows you to fly like an angel. Take yourself lightly whilst still being sincere.