Is there any proverb or idiom that conveys this meaning:" Don't rely on this world, since it is not loyal to man forever, today it is in your hand, tomorrow in mine" (actually it is a Persian saying and it implies that money, position, property, power... are not stable or eternal, so don't bond with/rely on this worldly world and just act and live like humans, and don't fight over gaining and keeping those things at any expense!)
For example: The dictators in other countries should learn a serious lesson from what happened to Qaddafi: the world is bound to no man and the six feet of earth make all men equal.
(I found this Jewish proverb, "the world is bound to no man", but I'm not sure if it is used by English speakers or not)
PS: in that Persian saying, "the world" has been resembled to an unfaithful or unreliable beloved whom you shouldn't expect to be with you forever! Maybe tomorrow she would abandon you and go with another one!, (in fact, here, the world means "life's deceitful/ temptating opportunities")