People reference the last sermon as "proof" for Muslims being required to follow both Qur'an and sunnah/hadith, but ignore the fact that there are THREE recorded versions of the last sermon. A reported 10,000 people attended that sermon, yet even then they couldnl't come to a consensus on which version was said. The third is the most ignored, yet it is also the one most in keeping with the teachings of the Qur'an. Hmmm....
Three versions of the Sermon:
1) I leave with you Quran and Sunnah, Muwatta, 46/3
2) I leave with you Quran and Ahl al-bayt (meaning the family of the Prophet) , Muslim 44/4, Nu2408; ibn hanbal 4/366; darimi 23/1, nu 3319.
3) I leave for you the Quran alone; you shall uphold it. Muslim 15/19, nu 1218; ibn Majah 25/84, Abu dawud 11/56.