And what are the things that should be completely understood by direct knowledge? The five grasping aggregates. These are called the things that should be completely understood by direct knowledge.

And what are the things that should be given up by direct knowledge? Ignorance and craving for continued existence. These are called the things that should be given up by direct knowledge.

And what are the things that should be developed by direct knowledge? Serenity and discernment. These are called the things that should be developed by direct knowledge.

And what are the things that should be realized by direct knowledge? Knowledge and freedom. These are called the things that should be realized by direct knowledge. These are the four things.”

Numbered Discourses 4.255 26. Insight Searches

“Mendicants, there are these four ignoble searches. What four? Someone liable to old age searches only for what grows old. Someone liable to sickness searches only for what gets sick. Someone liable to death searches only for what dies. Someone liable to become corrupted searches only for what is defiled. These are the four ignoble searches.