The Sunna is the practice and example of Muhammad, and is the second authority for 'Muslims' besides the Quran.
A Hadith is a reliably transmitted report of what Muhammad allegedly said, did, or approved. Belief in the divine inspiration of the sunna is as important in the 'Islamic' faith as belief in the Quran.
Sahih Al-Bukhari HadithHadith 7.822Narrated byAlqama
'Abdullah cursed those women who practiced tattooing and those who removed hair from their faces and those who created spaces between their teeth artificially to look beautiful, such ladies as changed what Allah has created. Um Ya'qub said, "What is that?" 'Abdullah said, "Why should I not curse those who were cursed by Allah's Apostle and are referred to in Allah's Book?" She said to him "By Allah, I have read the whole Qur'an but I have not found such a thing. 'Abdullah said, "By Allah, if you had read it (carefully) you would have found it. (Allah says:) 'And what the Apostle gives you take it and what he forbids you abstain (from it).' - (59.7)
Sahih Al-Bukhari HadithHadith 8.689Narrated bySaid bin Ubada Al Ansari
that he consulted the Prophet about a vow that had been made by his mother who died without fulfilling it. The Prophet gave his verdict that he should fulfill it on her behalf. The verdict became Sunna (i.e. the Prophet's tradition).
Sahih Al-Bukhari HadithHadith 9.387Narrated byAbu Musa
The Prophet said, "My example and the example of what I have been sent with is that of a man who came to some people and said, 'O people! I have seen the enemy's army with my own eyes, and I am the naked warner; so protect yourselves!' Then a group of his people obeyed him and fled at night proceeding stealthily till they were safe, while another group of them disbelieved him and stayed at their places till morning when the army came upon them, and killed and ruined them completely So this is the example of that person who obeys me and follows what I have brought (the Qur'an and the Sunna), and the example of the one who disobeys me and disbelieves the truth I have brought."
Sahih Al-Bukhari HadithHadith 9.381Narrated byHudhaifa
Allah's Apostle said to us, "Honesty descended from the Heavens and settled in the roots of the hearts of men (faithful believers), and then the Qur'an was revealed and the people read the Qur'an, (and learnt it from it) and also learnt it from the Sunna."Both Qur'an and Sunna strengthened their (the faithful believers)' honesty." (See Hadith No. 208)
Sahih Al-Bukhari HadithHadith 9.382Narrated byAbdullah
The best talk (speech) is Allah's Book (Qur'an), and the best way is the way of Muhammad, and the worst matters are the heresies (those new things which are introduced into the religion); and whatever you have been promised will surely come to pass, and you cannot escape (it).
Sahih Al-Bukhari HadithHadith 9.415Narrated byHumaid
I heard Muawiya bin Abi Sufyan delivering a sermon. He said, "I heard the Prophet saying, "If Allah wants to do a favor to somebody, He bestows on him, the gift of understanding the Qur'an and Sunna. I am but a distributor, and Allah is the Giver. The state of this nation will remain good till the Hour is established, or till Allah's Order comes."
*** The Sunna of Muhammad is deemed, in the tradition of his followers, as divinely inspired and hence second to if not equal to the Quran***