Giving us a moment to rest in the shade on an oppressively hot August afternoon, our Cambodian tour guide began to recount one of his favorite childhood stories. A practicing Buddhist, he was raised on a body of scripture and myth I had never heard. His religious beliefs are different from mine, with ideas about afterlife(s), ritual, and ethics that strike me as foreign. He is one of the kindest, most genuine people I have known, and I think his character has a lot to do with his foundational stories, like the following one he shared with four exhausted white Americans in the middle of an ancient Buddhist temple complex:
Kisa Gotami had an only son, and he died. In her grief she carried the dead child to all her neighbors, asking them for medicine, and the people said: “She has lost her senses. The boy is dead.”
At length Kisa Gotami met a man who replied to her request: “I cannot give thee medicine for thy child, but I know a physician who can.”
The girl said: “Pray tell me, sir; who is it?”
And the man replied: “Go to Sakyamuni, the Buddha.”
Kisa Gotami repaired to the Buddha and cried: “Lord and Master, give me the medicine that will cure my boy.”
The Buddha answered: “I want a handful of mustard-seed.” And when the girl in her joy promised to procure it, the Buddha added: “The mustard-seed must be taken from a house where no one has lost a child, husband, parent, or friend.”
Poor Kisa Gotami now went from house to house, and the people pitied her and said: “Here is mustard-seed; take it!”
But when she asked “Did a son or daughter, a father or mother, die in your family?” they answered her: “Alas the living are few, but the dead are many. Do not remind us of our deepest grief.”
And there was no house but some beloved one had died in it. 
I sensed that this story held within it a deep wisdom. Kisa Gotami wanted to raised her son from the dead, but the Buddha was able to guide her to what she truly needed: an expanded view of the universality of loss and death. Her inclination was to absorb her energy in addressing her personal concerns, but she found enlightenment only by being absorbed into the stories of others.
Henri J. M. Nouwen, a Catholic priest, passed through a period of depression during which he kept a journal to process and track his emotional life. His journal entries were later published as a book, The Inner Voice of Love. In one entry, he conceptualizes his pain as a momentary instance of a universal pain:
Paradoxically, therefore, healing means moving from your pain to the pain. When you keep focusing on the circumstances of your pain, you easily become angry, resentful, and even vindictive. You are inclined to do something about the externals of your pain in order to relieve it; this explains why you often seek revenge. But real healing comes from realizing that your own particular pain is a share in humanity’s pain. That realization allows you to forgive your enemies and enter into a truly compassionate life. 
Like the Buddha, Jesus also spoke of the mustard seed, but in this case as a symbol of faith:
If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you. (Matthew 17:20 KJV)
I wonder if Jesus and the Buddha were not talking about the same mustard seed.
 Excerpted from here with some formatting changes.
 Henri J. M. Nouwen, The Inner Voice of Love, pp. 103-4.