A long time ago there was a woman by the name of Kisa Gotami. Stories vary on who she was or where she came from, but this is what happened next - she married and gave birth to a baby boy that gave her great joy.
In time the boy grew and she delighted in him like no other thing. But one day the boy grew ill and died. In her grief, Kisa Gotami could not accept this and began to travel from house to house begging her neighbors for medicine to cure him.
No one, of course, had this medicine. They sent her away telling her this, but again her grief was so deep she could not comprehend. Finally she came to a doctor who realized what was occuring. He said to her "Go see the Buddha. He will have what you need."
She thanked him and hurried off, carrying the body of her dead son.
Buddha saw her approaching and knew immediately of her great suffering. He listened to her as she begged him to bring her child back to life, provide her with some medicine to cure him. Knowing that death was not reversible, he set her to the following task-
"Go find for me a mustard seed, and I will heal your child. But it must come from a household where no one has died or it will not work."
She eagerly did so, traveling from house to house within her village. Each door that she visited revealed that this household and that household had all experienced a death. She then traveled further to other nearby villages to beg for the same miraculous mustard seed. And every time was the same, with each household explaining that it had known death in some form.
After a time Kisa Gotami realized that there was nowhere that she could go to ask for a mustard seed that death had not touched. Thus enlightened, she returned to the Buddha at peace with the death of her son and began to study the Buddha's teachings.
Today a friend of mine died unexpectedly, and not for any of the reasons we feared she might, having been ill for quite some time with several ailments. It is most assuredly a shock to the system and one that I am still processing. I suspect she is probably just fine in Whatever Comes Next and it is us left behind having the most hard time of things. But in the meantime each time I begin to feel overwhelmed, or the thought "It isn't fair" crosses my mind, I will try to picture a tiny mustard seed, and gain comfort that this is the one common experience we all have. Everybody knows loss and death. This is not unique and we will live through it.