Now, these people (Submitters and Modernist) who reject the Sunnah, they will try to rationalize for their rejecting of the Sunnah by two things. One that the Qur’an is complete, and two that the Sunnah has not been preserved. When quoting a hadith to these people they might say “well that’s not in the Qur’an, why should I believe you? The Qur’an is complete, everything you need to know is in the Qur’an.” They might even try to quote you the verses of the Qur’an that show that the Qur’an is complete. Guess what? The Qur’an is complete, no one is arguing against that. If shown the evidence from the Qur’an, they would backtrack and say that the Sunnah has not been preserved. Saying the Sunnah does not need to be followed is Kufr. Saying the Sunnah has not been preserved is not Kufr, but it leads to Kufr. They say, “well Bukhari lived 300 years after the Prophet PBUH,” or “these Ahadith are like the gospels of Christianity.”
These two doubts can easily be refuted. Is the Qur’an complete? Yes it is. Is it sufficient in and of it self? Yes it is, but it orders us to go back to the Sunnah. The second doubt that they bring is that the Sunnah has not been preserved. The first way is to explain the long, detailed, dry, science of Hadith (Uloom ul Hadith). You explain how the Sunnah was preserved, how the Sahaba preserved it, how the Tabioon preserved it, how the Taba Tabioon preserved it, the history of this process. This is not something that can be explained in two minutes, this explanation will take quite some time. The second way to prove the preservation of the Sunnah is the short cut. This is a circular argument; it is full proof, and something that these people can NEVER refute. The fact that the Sunnah is part of the religion necessitates that it will be preserved; it is sufficient proof that Allah will preserve it.
“Verily We: it is we who have sent down the Dhikr (i.e. the Qur’ân and Sunnah) and surely, we will Guard it (from corruption)”
The fact that Allah SWT orders us to follow the Sunnah proves that Allah has protected the Sunnah. Allah says
“Allâh burdens not a person beyond his scope”
Allah says he does not burden a soul, with something it cannot handle. Allah would not order us to obey the Sunnah if he had not preserved it.