Actually, there is no contradiction between the authentic hadiths and the Qur’an. The Hadith is the second source of Islamic legislation; the first being the glorious Qur’an. So, the Hadith is one of the primary sources of sharia.
As for the differences among Muslim scholars, it should be clear that these differences, first and foremost, are related to branches (in Arabic: furu`) of shariah, rather than the main pillars of Islamic creed. Second, these differences in many cases have valid reasons and are described as mercy; therefore, it should not be a cause of confusion. To learn more on this issue, books like Ikhtilaaf (Juristic Difference): How and Why? should be read
In his response to this issue, Dr. Muzammil H. Siddiqi said:
The Qur’an and Hadith are the two primary sources of Islam. There can never be any contradiction between Qur’an and authentic Hadith. It is not correct to say that Hadith was compiled only 200 years after Prophet Muhammad’s (peace and blessings be upon him) death because there was a great number of hadiths in circulation during the time of the Prophet (peace and blessings be upon him). But most of the hadiths were compiled during the 2nd century of Hijrah.
Furthermore, the muhaddithun (Arabic for: Hadith scholars) spared no effort to verify the Hadith and distinguish between the sahih (Arabic for: authentic), da`if (Arabic for: weak) and mawdu` (Arabic for: fabricated).
Having said this, there has been difference in interpretation with regard to both the Qur’an and Hadith. This is due to many factors including understanding the language and historical contexts and backgrounds. But difference of interpretation cannot be taken as a ground for denying or rejecting the source wholeheartedly.