The Tibetans have very funny idioms that are very earthly and easy to remember.
One of their idioms is about a crippled young boy that is somehow on the roof of a house. The boy falls off the roof, and lands on a wild donkey below. The donkey is startled, and starts sprinting with the crippled boy still riding its back. The villagers scream at the young boy, telling him to get off. The boy refuses, and replies,
“What are the chances that someone like me will get a chance to ride a wild ass? Now is the time to ride!”
While this idiom probably came from several hundred years ago, the idiom is actually an easy to remember reference to this precious human life. Getting a human life endowed with certain freedoms, conditions and mental aptitudes favorable towards practice are difficult to find.
They say that the likelihood of getting a human life where one is interested and can actually practice Dharma is like the likelihood of a blind turtle surfacing from the ocean every 100 years, and somehow sticking its head through a constantly moving yoke that lies on the surface.
Or maybe as likely as a crippled boy falling on a wild ass’ and riding away.