At Sāvatthi.

Then the Blessed One, having taken a small amount of dust on the tip of a fingernail, addressed the bhikkhus: "What do you think, bhikkhus, which is more, this small amount of dust on the tip of the fingernail or this great earth?"

"Indeed, venerable sir, the great earth is more. The small amount of dust on the tip of the fingernail put by the Blessed One does not come to a hundredth part, nor to a thousandth part, nor to a hundred-thousandth part compared to the great earth."

"Just so, bhikkhus, few are the beings who are reborn among humans; far more numerous, however, are the beings who are reborn elsewhere, apart from humans."

Therefore, bhikkhus, you should train yourselves thus: 'We will dwell diligently.' Thus, bhikkhus, you should train yourselves."