[817] Origin at Sāvatthī. Now at that time the group-of-six bhikkhus sat swinging their arms in an inhabited area, letting their arms dangle. …
"I will not sit swinging my arms in an inhabited area" — thus the training is to be undertaken.
One should not sit swinging the arms in an inhabited area; one should sit with the arms held in. Whatever bhikkhu, out of disrespect, sits swinging his arms in an inhabited area, letting an arm dangle, incurs an offence of wrong-doing (dukkaṭa).
There is no offence for one who acts unintentionally, for one lacking mindfulness, for one who does not know, for one who is sick, for one who has gone to a lodging, in emergencies, for one who is mad, or for the first offender.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.