Dukkarasutta

Suttapiṭaka · Saṁyuttanikāya · Sagāthāvaggasaṁyutta · Vol. 15 · Section 37

[37] [The Blessed One:] "For how many days could one live the ascetic life (sāmañña), if one did not restrain the mind (citta)? At every step one would founder, fallen under the sway of one's intentions (saṅkappa). As a tortoise draws its limbs into its own shell, so a bhikkhu, gathering in the mind's thoughts (manovitakka), independent, not harassing another, fully quenched (parinibbuta), would not blame anyone." The Eighth: The Hirisutta

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.