374. As soon as he has considered the origin and destruction of the elements (khandha) of the body, he finds happiness and joy which belong to those who know the immortal (Nirvâna).
375. And this is the beginning here for a wise Bhikshu: watchfulness over the senses, contentedness, restraint under the law; keep noble friends whose life is pure, and who are not slothful.
DHAMMAPADA, Chapter 25. THE BHIKSHU (MENDICANT)