Mahāhatthipadopama Sutta
Sāriputta addresses the monks at Jetavana and tells them that, just as the foot of every creature will fit in the elephant’s footprint, even so are all right states of mind comprised within the Four Noble Truths. He then goes on to explain that suffering (dukkha) consists of the five aggregates of attachment (upādānakkhandhā) — form, feeling, perception, formations, and consciousness. The constituents of these attachments are the four primary elements: earth, water, fire, and air. Each element is of two kinds personal (ajjhatta) and external (bahiddhā) — and each is transient and subject to decay. The chain of causation entails all that makes up the five attachments. Where there is eye intact, on which external shapes come to focus, and where there is developed pertinent material to sustain it, there is developed a manifestation of the pertinent section of consciousness. Thus arises the aggregate of form; similarly with the others. M.i.184‑91.