How can a Hadith be judged if some scholars have authenticated or deemed it good, while others have declared it weak? Is it obligatory to verify every Hadith not found in the Two Sahihs? And how can the Sunnah be preserved with such differences regarding Hadith?

There is no strangeness in the same scholar's ruling on a hadith changing, due to a shift in his ijtihad (independent reasoning) or the emergence of something previously hidden from him. Whoever is among the distinguished people of knowledge and their students should exert ijtihad and act upon their ijtihad. As for those who are not at that level, they should ask the people of knowledge and emulate the one they deem most reliable if there is a difference of opinion. Preserving the Sunnah is essential for preserving the Qur’an, which cannot be understood except through it, and Allah has preserved it for the preservation of His Book and His Sharia. The differences among hadith scholars are a manifestation of the preservation of the Sunnah, the maturity and breadth of this science, and its sufficiency in refuting the fabrications of falsehood-mongers. Muslims have been unique in these scientific controls for receiving narrations.