Indeed the correct way of understanding the real Islam is to refer to the Holy Quran as the basis for all knowledge and then understanding the Sunnah and Hadith in its light. Anything that cannot be linked back to the Quran cannot be declared an integral part of Islam. We must be very careful when we assume that something is or is not part of Islam. Allah has protected the Holy Book for this very purpose that no matter how much time passes the word of Allah remains pure and provides guidance to those who truly want to submit to his will and stay on course to becoming true Muslims.
The values, injunctions, and the principles enshrined in the Book form the corner stone of the Islamic polity and the limits laid down by it provide the framework within which the laws of the Islamic State may be formulated. These principles, or limits, or framework, are immutable, but the statutes made by the State within these four corners are open to modification and change according to the needs of the times.

The Qur’an is the last of the Divine Books, because Messenger-hood ended with Muhammad. No subsequent human opinion or pronouncement in matters of deen, therefore, can be recognized as authoritative; nor can any man-made law repugnant to the Qur’an be regarded as binding upon the Muslims. The Qur’an is a book of guidance for all mankind and transcends the barriers of time and space. The Islamic State is an instrument for the enforcement of the Laws and Injunctions embodied in the Qur’an.
May Allah guide us and have mercy on us. Ameen.
Abdul Momin
http://www.quransunnat.com