Imaam Hasan Radiyallahu 'Anhu says, (my younger brother) Husayn said:
"I asked my father (Sayyidina 'Ali Radiyallahu 'Anhu) about the conduct of Rasulullah Sallallahu 'Alayhi Wasallam in his assemblies' He replied.. 'Rasulullah Sallallahu 'Alayhi Wasallam was always happy and easy mannered. There was always a smile and a sign of happiness on his blessed face. He was soft-natured and when the people needed his approval, he easily gave consent. He did not speak in a harsh tone nor was he stone-hearted. He did not scream while speaking, nor was he rude or spoke indecently. He did not seek other's faults. He never over-praised anything nor exceeded in joking, nor was he a miser. He kept away from undesirable language and did not make as if he did not hear anything. If he did not agree with the next person's wish he did not make that person feel disheartened, nor did he promise anything to that person. He completely kept himself away from three things: from arguments, pride and senseless utterances. He prohibited people from three things. He did not disgrace or insult anyone, nor look for the faults of others, he only spoke that from which thawaab and reward was attained. When he spoke, those present bowed their heads in such a manner, as if birds were sitting on their heads. (They did not shift about, as birds will fly away on the slightest move). When he completed his talks, the others would begin speaking. (No one would speak while Sayyidina Rasulullah Sallallahu'Alayhi Wasallam spoke. Whatever one wanted to say, it would be said after he had completed speaking). They did not argue before him regarding anything. Whenever one spoke to him the other would keep quiet and listen till he would finish. The speech of every person was as if the first person was speaking. (They gave attention to what every person said. It was not as is generally found that in the beginning people pay full attention, and if the talk is lengthened they became bored, and begin to pay less attention). When all laughed for something, he would laugh too. The things that surprised the people, he would also show his surprise regarding that. (He would not sit quietly and keep himself aloof from everyone, but made himself part of the gathering). He exercised patience at the harshness and indecent questions of a traveller. (Villagers usually ask irrelevant questions. They do not show courtesy and ask all types of questions. Sayyidina Rasulullah Sallallahu 'Alayhi Wasallam did not reprimand them but exercised patience). The Sahaabah would bring travellers to his assemblies (so that they themselves could benefit from the various types of questions asked by these people, and also hear some questions regarding which they themselves, due to etiquette, would not ask). Rasulullah Sallallahu 'Alayhi Wasallam' would say: 'When you see a person in need, then always 'help that person'. (If someone praised him, he would detest it). If someone, by way of thanks praised him, he would remain silent, (because it is necessary that one 'thank a person for a good favour or good deed. It is like one fulfilling one's duty. Some of the 'ulama have translated this as: 'If one did not exceed in praising him, he would keep silent'. That means if he exceeded he would prohibit him). He did not interrupt someone talking and did not begin speaking when someone else was busy speaking. If one exceeded the limits he would stop him or would get up and leave (so that that person would stop)"
English reference: Book 47, Hadith 334
Arabic reference: Book 48, Hadith 351