[213] Bhikkhus, suppose there were a young tree. A man would from time to time clear about its roots, from time to time supply soil, from time to time supply water. Then indeed, bhikkhus, that young tree, with that as its nutriment (āhāra), with that as its sustenance (upādāna), would come to growth, increase, and abundance. In just the same way, bhikkhus, in one who dwells contemplating gratification (assāda) in things that are conducive to the fetters (saññojaniyā dhammā), craving (taṇhā) increases. With craving as condition, clinging (upādāna) … Thus is the origin of this whole mass of suffering (dukkha).
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.