Which of the following three approaches is correct and which is incorrect: Sufficing with the Quran, based on Allah's saying: ﴿We have not neglected anything in the Register,﴾ or sufficing with the Sunnah, or taking both of them together?

The source of the Quran and the authentic Sunnah of the Prophet is Allah, Glory be to Him, and obedience to Allah and His Messenger are inextricably linked. It is not permissible to differentiate between the words of Allah and the words of His Messenger, for both are revelation. The Sunnah clarifies and explains the Book, so it is impossible to differentiate between that which clarifies and the clarification itself. Returning to Allah means returning to the Quran, and returning to His Messenger means returning to the Sunnah. Therefore, whoever obeys the Messenger has obeyed Allah, and obedience to him is independently obligatory. Whoever claims self-sufficiency with the Quran apart from the Sunnah is misguided, because the Sunnah elaborates on what is general in the Quran. As for the verse, "We have not neglected in the Book a thing," it does not indicate that the Quran encompasses all details; because "the Book" here may be interpreted as the Preserved Tablet. And if it is interpreted as the Quran, the meaning is that the Quran has not neglected the fundamentals and universals of religion, and the details thereof are for the Sunnah.