It’s as if there were a bag with openings at both ends, filled with various kinds of grains, such as fine rice, wheat, mung beans, peas, sesame, and ordinary rice. And a person with clear eyes were to open it and examine the contents: ‘These grains are fine rice, these are wheat, these are mung beans, these are peas, these are sesame, and these are ordinary rice.’ In the same way, a mendicant examines their own body, up from the soles of the feet and down from the tips of the hairs, wrapped in skin and full of many kinds of filth. … As they meditate like this—diligent, keen, and resolute—memories and thoughts tied to domestic life are given up. Their mind becomes stilled internally; it settles, unifies, and becomes immersed in samādhi. That too is how a mendicant develops mindfulness of the body.

Furthermore, a mendicant examines their own body, whatever its placement or posture, according to the elements: ‘In this body there is the earth element, the water element, the fire element, and the air element.’