[873] Origin at Sāvatthī. Now at that time the group-of-six bhikkhus (chabbaggiyā), while standing, taught the Dhamma to a person who was seated. … "I will not, while standing, teach the Dhamma to a person who is seated and not sick" — thus should the training be undertaken.
The Dhamma should not be taught by one who is standing to a person who is seated and not sick. Whatever bhikkhu, out of disrespect, while standing teaches the Dhamma to a person who is seated and not sick, incurs an offense of wrongdoing (dukkaṭa).
There is no offense: if it is unintentional; if he is unmindful; if he does not know; if he is sick; in emergencies; if he is insane; if he is the first offender.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.