[181] Now at that time the bhikkhus (bhikkhu) of the group of six were learning the worldly philosophy (lokāyata). People criticized, complained, and spread it about, saying: "… like householders who enjoy sensual pleasures." Bhikkhus heard those people criticizing, complaining, and spreading it about … Then those bhikkhus reported this matter to the Blessed One. …
"Bhikkhus, would one who sees essence in the worldly philosophy attain growth, increase, and abundance in this Dhamma and Discipline (dhammavinaya)?"
"Certainly not, venerable sir."
"Or would one who sees essence in this Dhamma and Discipline learn the worldly philosophy?"
"Certainly not, venerable sir."
"Bhikkhus, the worldly philosophy is not to be learned. Whoever should learn it commits an offense of wrong-doing (dukkaṭa)."
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.