The Messenger of Allah used to say:
The best amongst you are those who have the best manners and character.
(Related by al-Bukhari)
Rasulullah said: There is none heavier in the scales of the Hereafter than good character, (Hadith narrated by al-Tirmidhi and Abu Daud).
Rasulullah also mentioned: Bad manners are a misfortune. (Hadith narrated by Imam Ahmad).
A Muslim is one whom other people are safe from his tongue and his hand.
(Hadith narrated by Bukhari).
...Abu Darda' reported that the Prophet of Allah, upon him be peace, said, "Nothing is weightier on the Scale of Deeds than one's good manners."
Hadith - Bukhari's Book of Manners #271, Abu Dawud, Tirmidhi, Ahmad, and Ibn Hibban.
Abu Huraira, r.a., said, "I heard Abu al Qasim (the Prophet saaws), say, 'The best among you in Islam are those with the best manners, so long as they develop a sense of understanding.' "
Hadith - Bukhari's Book of Manners #286 and Ahmad
... 'Abd Allah ibn 'Amr said, "The Prophet of Allah, upon him be peace, was never obscene or coarse. Rather, he used to tell us that the best among us were those with the best manners."
Hadith - Sahih Bukhari, Muslim, and Tirmidhi
... Anas said, "I served the Prophet of Allah, upon him be peace, for ten years. During that time, he never once said to me as much as 'Oof' if I did something wrong. He never asked me, if I had failed to do something, 'Why did you not do it?,' and he never said to me, if I had done something wrong, 'Why did you do it?' "
Hadith - Sahih Bukhari, Muslim and Ahmad
... Abu Huraira, r.a., said that the Prophet of Allah, saaws, said, "If one has good manners, one may attain the same level of merit as those who spend their nights in prayer."
Hadith - Bukhari's Book of Manners # 285, Hakim, and Abu Dawud
... Abu Hurairah reported that the Prophet of Allah (saaws) said, "And what is most likely to send people to Paradise? Being conscious of Allah and good manners."
Hadith - Bukhari's Book of Manners # 290, Tirmidhi, Ibn Majah, and Ahmad
... Nawas ibn Sam'an reported that the Prophet of Allah, saaws, was asked about doing good and evil. He replied, "Doing good is having good manners. Doing evil is what troubles you inside and what you would not like others to know about."
Hadith - Bukhari's Book of Manners # 296, Muslim, Tirmidhi, Darimi, Abu 'Awanah, Hakim, and Ibn Hibban.
The Prophet of Allah, saaws, said, "He who does not show mercy to our young or show esteem for our elders is not one of us."
Hadith - Bukhari's Book of Manners #360, Abu Dawud, Tirmidhi, and Hakim
http://muttaqun.com/manners.html