คนส่วนมากต้องตกนรก คำเตือนจากพระไตรปิฎก
Summary
The image of dust on a fingernail against the great earth is a direct and heavy warning: very few return to a good destination compared with those who fall.
The purpose is not to frighten but to press against complacency, and to send the listener back to the Four Noble Truths in earnest.
Heaven, the deva realms and the brahma realms are good destinations, but they are not liberation. While ignorance and craving remain, the round continues.
Key points
The image is deliberately heavy
The ratio of fingernail dust to the great earth is not scare-mongering. It is a statement of scale.
A good destination is not safety
A fortunate rebirth is the result of good kamma, and results run out — which is why the teaching does not stop there.
The exit is through ignorance and craving
While those two remain, accumulating merit only buys time.
The warning is for acting on, not for dreading
What follows the image in the sutta is a return to the Four Noble Truths, not an invitation to anxiety.