[875] Origin at Sāvatthī. Now at that time the group-of-six bhikkhus (chabbaggiyā), walking off the path, taught the Dhamma to one walking on the path. …
"I will not, while walking off the path, teach the Dhamma to a person who is not sick walking on the path" — thus should the training be undertaken.
The Dhamma should not be taught by one walking off the path to a person who is not sick walking on the path. Whichever bhikkhu, out of disrespect, walking off the path, teaches the Dhamma to a person who is not sick walking on the path, incurs an offence of wrong-doing (dukkaṭa).
There is no offence: if it is unintentional; if he is unmindful; if he does not know; if the person is sick; in emergencies; if he is insane; if he is the first offender (ādikammika).
The Three Miscellaneous Rules — 1.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.