Obey God & The Messenger
Many people site the Quraanic Verses that command us to Obey Allah and Obey the Messenger, and say that Obeying Allah and obeying the Messenger are two different things - Obeying Allah is to obey the Quraan and obeying the Messenger is to obey the books of Hadith. They point that if obeying the Messenger was the same thing as obeying Allah's Quraan, then Allah would have only said Obey Allah. These people say that Allahs inclusion of obey the Messenger implies that the Messenger is saying EXTRA things outside of the Quraan that we must obey.
The thing that many proponents of Hadith forget is that Allah does not leave it to speculation as to what the people are to obey. The Ayaat do not end at Obey Allah and obey the Messenger, but they continue to include what the duty of the Messenger is:
And obey Allah and obey the messenger and be cautious; but if you turn back, then know that only a clear deliverance of the message is (incumbent) on Our messenger <wa ma_ alar rasu_li il lal balaghul mubin (5:92)