There's a great folktale that goes along with that one. Story goes (and forgive me, for it's been years since I heard it) that there once was a great king whose chambers were filled with absolutely everything you could imagine, for he had a penchant for collecting - a greed, perhaps. He had gold and jewels galore, he had the rights to the best land within and outside his kingdom. He had the most talented people in the land in his court, to entertain, amuse, converse with him. But, as every story goes, he was not satisfied. He had objects of desire, objects of sadness, things that could cause immense pain, and others that could cure many diseases, but it was not enough. He wanted the perfect object, the most beautiful and utterly fine treasure that ever did exist.

So he put out a call with a reward - the largest reward of all: everything he owned. Such was his desire for this object. And for years upon years he had streams of people coming to him with wondrous things: diamonds as big as a man's skull, a steed that could run for leagues and never tire, an army that would obey his every single command no matter what, women as beautiful as the fresh sun of dawn on the treetops - but he turned them all away.

In the end, he began to die. It was a slow, painful, and mysterious death. His people tried desperately to cure him - for despite his greed, he was a kind ruler, and they lived prosperously and happily - but to no avail. His cries would ring out from his tower every night, making it nigh impossible to sleep. His city slowed, and began to sicken, as its people dredged by, day by day, with little rest.

Eventually, after months of this unrelenting pain, just as the king had given in, resolving that his sickness was caused by his desire burning into his heart, a traveller arrived at his gates, claiming that he had what the king was seeking. He had little with him: no horse nor carriage, a bag so small that it surely could hold no treasures. The city guard were doubtful, fearing that this lone traveller had come to take the king's life and his treasure, but let him in regardless, for hope still lay in their hearts, no matter how dormant. The traveller had claimed that the treasure he had brought would bring the king both happiness and sadness, that it could be held and treasured in times of both victory and defeat, wealth and famine. So they let him in. They were not foolish, however, and accompanied him to the king's chambers.

They watched as the traveller slowly walked up to the king's bed, where he had lain for the past month, unable to move. The traveller leaned in and whispered something in the king's ear. Their beloved king died, then, staring into the traveller's eyes, mouth open only slightly, a soft sigh that was heard throughout the room. Panicked, the guards sprung into action, fearing that the worst had happened, and that this traveller had somehow assassinated their already-dying king.

"Peace, friends!" the traveller exclaimed. "I did not kill your king, I simply gave him what he desired. Once he had that, he no longer had anything to tie him to this realm." The guards remained suspicious, but there was something about this traveller that made his words ring true. One of them asked:

"What did you whisper to him? What was it that the king desired?"

"I gave him the most wondrous treasure there is. It can bring joy and sadness. It has no material wealth, nor any physical presence. It is but a phrase," the traveller replied.

"And what is that phrase?" the guard asked quietly, almost afraid to hear the answer.

"This, too, shall pass."