Qaradawi: The Enemies of the Sunnah
In our times, new enemies of the Sunnah have arisen. Some are from outside our lands [like the non-Muslims].. …Others are from within our lands, from amongst those influenced by the former, directly or indirectly.
Among the doubts of the enemies of the Sunnah, which they repeat continually, is their claim that the Quran suffices without the Sunnah, in consideration of the fact that there is detailed exposition in it of everything, as Allah said: ‘We revealed to you the and Book as a clarification of everything and as a guidance and as a mercy and good tidings for those who have surrendered.’ (al Nahl, 89). They make the same claim also because (they say) Allah vouchsaved the preservatoin of the Quran, but not that of the Sunnah.
The answer to that claim is that the Sunnah is without a doubt the clarification of the Quran. It is that which details what is summary in the Quran, particularizes what is general in it, and qualifies what is absolute in it. If the Sunnah were not there, we would not know the details of the rites (prayer, fasting, zakat, pilgrimage) and other necessary and essential duties. For this reason, Allah said: ‘And We are revealing to you the Remembrance so that you make clear to the people what We have revealed to them, and perhaps they may reflect.’ (al Nahl, 44)
Moreover, it is the Quran itself that has enjoined obedience to the Messenger, just as it has enjioned obedience to Allah: ‘Say, Obey Allah and obey the Messenger.’ (al-Nur, 54); ‘O believers: Obey Allah and obey the Messenger, and the people of authority amongst you; and if you have a dispute on any matter, refer it to Allah and the Messenger.’ (al-Nisa, 63).
The scholars were unanimous on the point that referred to Allah means referring to His book, and referring to the Messenger means referring to his Sunnah.
As for the claim that Allah has preserved only the Quran – namely, that He guarantees its preservation, and does not guarantee the preservation of the Sunnah… …[as] explained by al-Shatibi in al-Muwafaqat: that the preservation of the Quran vouchsafes that of the Sunnah because the latter is the exposition of the former. For the preservation of what is clarified necessarily entails the preservation of what is clarifying it.
Approaching the Sunnah: The Status of the Sunnah, Qaradawi

