From: ,
Theravāda Vinaya Theravāda Collection on Monastic Law
Mahāvibhaṅga The Great Analysis
Sekhiyakaṇḍa The chapter on training
Kabaḷavagga The subchapter on mouthfuls
41. Anāhaṭasikkhāpada Opening the mouth
Origin story
Tena samayena buddho bhagavā sāvatthiyaṁ viharati jetavane anāthapiṇḍikassa ārāme. At one time the Buddha was staying at Sāvatthī in the Jeta Grove, Anāthapiṇḍika’s Monastery.
Tena kho pana samayena chabbaggiyā bhikkhū anāhaṭe kabaḷe mukhadvāraṁ vivaranti …pe…. At that time the monks from the group of six opened their mouths without bringing a mouthful to it. …
Final ruling
“Na anāhaṭe kabaḷe mukhadvāraṁ vivarissāmīti sikkhā karaṇīyā”ti. “‘I will not open my mouth without bringing a mouthful to it,’ this is how you should train.”
Na anāhaṭe kabaḷe mukhadvāraṁ vivaritabbaṁ. One should not open one’s mouth without bringing a mouthful to it.
Yo anādariyaṁ paṭicca anāhaṭe kabaḷe mukhadvāraṁ vivarati, āpatti dukkaṭassa. If a monk, out of disrespect, opens his mouth without bringing a mouthful to it, he commits an offense of wrong conduct.
Non-offenses
Anāpatti—There is no offense:
asañcicca …pe… if it is unintentional;
if he is not mindful;
if he does not know;
if he is sick;
if there is an emergency;
if he is insane;
ādikammikassāti. if he is the first offender.
Paṭhamasikkhāpadaṁ niṭṭhitaṁ. The first training rule is finished.