AN 2.9
PTS: A i 51
Lokapala Sutta: The Bright Protectors
translated from the Pali by
John D. Ireland
Alternate translation: Thanissaro
This sutta (plus a concluding series of verses) also appears at Iti 42.

"Bhikkhus, these two bright principles protect the world. What are the two? Shame and fear of wrongdoing. If, bhikkhus, these two bright principles did not protect the world, there would not be discerned respect for mother or maternal aunt or maternal uncle's wife or a teacher's wife or the wives of other honored persons, and the world would have fallen into promiscuity, as with goats, sheep, chickens, pigs, dogs, and jackals. But as these two bright principles protect the world, there is discerned respect for mother... and the wives of other honored persons."