SN56.48 — Dutiyachiggaḷayuga Sutta

Disciples, suppose this great earth were covered with water. A man would throw a yoke with a single hole into it. The east wind would carry it west, the west wind would carry it east, the north wind would carry it south, and the south wind would carry it north. There would be a blind turtle. It would come up to the surface once every hundred years. What do you think would that blind turtle, coming up once every hundred years, insert its neck into that single-hole yoke?

It would be a rare occurrence, venerable sir, that the blind turtle, coming up once every hundred years, would insert its neck into that single-hole yoke.

Even so, it is a rare occurrence to be born as a human. It is a rare occurrence for a Tathāgata, an Arahant, a Perfectly Enlightened One, to arise in the world. It is a rare occurrence for the Dhamma and Discipline proclaimed by the Tathāgata to shine in the world.

Now you have gained this human state, a Tathāgata has arisen in the world, and the Dhamma and Discipline proclaimed by the Tathāgata shines in the world. Therefore you should make an effort to understand: This is suffering... This is the path leading to the cessation of suffering.