From:
Theravāda Vinaya Theravāda Collection on Monastic Law
Mahāvibhaṅga The Great Analysis
Sekhiyakaṇḍa The chapter on training
Ujjagghikavagga The subchapter on laughing loudly
17. Bāhuppacālakasikkhāpada 17. The training rule on swinging the arms
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 bāhuppacālakaṁ antaraghare gacchanti bāhuṁ olambentā …pe…. At that time the monks from the group of six were swinging and dangling their arms while walking in inhabited areas. …
“Na bāhuppacālakaṁ antaraghare gamissāmīti sikkhā karaṇīyā”ti. “‘I will not swing my arms while walking in inhabited areas,’ this is how you should train.”
Na bāhuppacālakaṁ antaraghare gantabbaṁ. One should not swing one’s arms while walking in an inhabited area;
Bāhuṁ paggahetvā gantabbaṁ. one should walk keeping one’s arms steady.
Yo anādariyaṁ paṭicca bāhuppacālakaṁ antaraghare gacchati bāhuṁ olambento, āpatti dukkaṭassa. If a monk, out of disrespect, swings and dangles his arms while walking in an inhabited area, he commits an offense of wrong conduct.
Anāpatti—There is no offense:
asañcicca …pe… if it is unintentional;
ādikammikassāti. if he is the first offender.
Sattamasikkhāpadaṁ niṭṭhitaṁ. The seventh training rule is finished.