First, proofs of those who say that the Sunnah may constitute a new ruling:
1- They said: There is no objection that the Sunnah may constitute a new ruling as long as the Messenger of Allah (peace be upon him) is infallible. Allah (Glory be to Him) may command His Messenger to convey His Rulings to the people by any way, whether that way was the Qur'an or something else. As long as it is intellectually permissible with one accord, so why do not we adopt that view? (1)
2- Indeed, the texts reported in the Qur'an which prove the obligation of following the Messenger (peace be upon him) in his commands and prohibitions with no difference between the explanatory Sunnah, the confirming Sunnah, or the Sunnah which constitutes new rulings. These Ayahs, which we have mentioned some of them, indicate that they are general and not limited.
Moreover, Allah's Saying: "But no, by your Lord, they can have no Faith, until they make you (O Muhammad peace be upon him) judge in all disputes between them, and find in themselves no resistance against your decisions, and accept (them) with full submission," (2) proves the permissibility of saying that the Sunnah constitutes new rulings; and that was previously explained in the view of Al Shafi`y. (3)
Ibn Al Qayyim said: "Verily, the Sunnah, which constitutes a new ruling that was not mentioned in the Qur'an, is a new legislation from the Prophet (peace be upon him) that must be obeyed and it is not permissible to disobey it. This does not mean that we advance the Sunnah to the Qur'an, but this is part of what Allah said about obeying His Messenger. If the Messenger (peace be upon him) is not obeyed in this part, what is the meaning of obeying him? If he is not obeyed except in things that match the Qur'an, he would not have a special obedience. Allah (may He be Exalted) says: "He who obeys the Messenger (Muhammad peace be upon him), has indeed obeyed Allâh." (4) Allah also told us: "And whatsoever the Messenger (Muhammad peace be upon him) gives you, take it; and whatsoever he forbids you, abstain (from it)." (5)
Allah (Glory be to Him) gave him the validity to legislate because He appointed him to explain His Words, moreover his entire words are explanations to the words of Allah. Furthermore, the extra meaning is part of explanation and there is no difference whether the Sunnah mentioned the number of Tawaf (Circumambulating the Ka`bah) and the number of Rak`ah (unit of Prayer) in Salah, and between recalling tranquility in Salah, the necessity of reciting Surat Al Fatihah, and having the intention in any work because all these actions are meant by Allah to worship Him properly. As long as this is meant, the Sunnah comes to explain all these rulings from all aspects, even when constituting new rulings, they are explanation to the objectives of Allah when He commanded people to follow and obey the Messenger. So, there is no difference between these matters and Salah, Zakah, Hajj, and Tawaf, but this is the explanation of a particular command and that is the explanation of the general commands. (6)
3- May Hadiths indicate that the Shari`ah is composed of two fundamentals: The Qur'an and the Sunnah. The Sunnah does not have the same rulings of the Qur'an, so it is obligatory to follow the rulings of the Sunnah as well as the rulings of the Qur'an, such as the Prophet's saying: "Behold! I have been given the Qur'an and something like it. yet the time is coming when a man replete on his couch will say: Keep to the Qur'an; what you find in it to be permissible treat as permissible, and what you find in it to be prohibited treat as prohibited. Indeed, what the Messenger of Allah prohibited is as what Allah prohibited. Beware! The domestic ass, beasts of prey with fangs, a find belonging to confederate, unless its owner does not want it, are not permissible to you. If anyone comes to some people, they must entertain him, but if they do not, he has a right to mulct them to an amount equivalent to his entertainment." (7)
It is not hidden that the prohibition of domestic donkeys and other types do not exist in the Qur'an.
It is also not hidden that the meaning of the Prophet's saying: "The like" is something completely independent as Ash-Shawkany said. If we admit the inclusiveness of the Qur'an, there is no harm to follow the Sunnah as long as it was revealed from Allah. (8)
4- Induction denoted that there are countless matters in the Sunnah to which the Qur'an did not refer, such as the prohibition of marrying a woman along with her paternal or maternal aunt, the prohibition of eating domestic donkeys and every fanged beast of prey, blood money, releasing of prisoners, and that a Muslim cannot be killed for an infidel...etc. (9)
This is supported by inducing the books of Fiqh according to any school of Fiqh where you can find in many chapters these phrases: "The general rule in its legitimacy is the Qur'an and the Sunnah." or this phrase: "The general rule in its legitimacy is the Sunnah" or anything that may lead to this meaning.
5- If it is not permissible that the Sunnah constitutes a new ruling, that would be for a reason or impediment and when we search the Shari`ah proofs, which the opponents have mentioned and which we shall mention later, we would not have found that reason or impediment. There is no doubt that Allah (may He be Exalted) may command His Messenger to convey the ruling which He did not mention in His Book, but rather He may reveal every ruling without words then reveals the Book thereafter to confirm or explain it or even does not reveal a book in the first place because it is not a condition that He sends a Messenger and reveals a book to him: "He cannot be questioned as to what He does, while they will be questioned." (10)
There is no doubt that the Prophet (peace be upon him) is infallible, which is a miracle, and cannot make a mistake in conveying any ruling that was revealed to him: By a spoken or non-spoken revelation, and whether the ruling is independent, explaining, or confirming, but he is infallible and cannot make a mistake in conveying the message if the entire Shari`ah was revealed in non-spoken revelation and the people will be accountable for that and they have to follow it. There is no doubt that the Sunnah is a type of revelation, so it is true and it is permissible to be independent.
There is no doubt that the presence of another type (which is the Qur'an) with the Sunnah and both were revealed from Allah and are hold as sources of Shari`ah cannot deny that the Sunnah is independent even though the Qur'an is characterized by things which do not exist in the Sunnah and does not entail that it is the only source of Shari`ah.
So, where is the impediment or the reason for not counting the Sunnah independent in constituting new rulings? (11)
6- If it is not permissible that the Sunnah constitutes new rulings, it is not permissible that it confirms or explains the rulings of the Qur'an because confirmation is a branch of constitution and explanation is a type of independent ruling, and because any impediment of independence is a barrier for explanation. An impediment is made to prevent deficiency and deficiency in any of them leads to the ignorance of the fully competent person of the ruling of Allah and not doing it properly. (12)
(1) As-Sunnah Wa Makanataha Fy At-Tashri` Al Islamy p. 381, and Hujjiyyat As-Sunnah, p. 508.
(2) Surat An-Nisa' 65.
(3) As-Sunnah Wa Makanataha Fy At-Tashri` Al Islamy p. 381, and Hujjiyyat As-Sunnah, p. 509.
(4) Surat An-Nisa': 80.
(5) Surat Al Hashr: 7.
(6) I`lam Al Muwaqqi`in (4 - 84 - 85 - 97) Edition of Ibn Al Jawzy Print House.
(7) Reported by Abu Dawud in his Sunan in the book of the Sunnah, chapter on the obligation of adhering to the Sunnah, No. 4604, its sources were previously mentioned.
(8) As-Sunnah Wa Makanataha Fy At-Tashri` Al Islamy, p. 383, and Hujjiyyat As-Sunnah, p. 514.
(9) Al Muwafaqat (4/16)
(10) Surat Al Anbiya': 23.
(11) Hujjiyat As-Sunnah p. 507, 508.
(12) Ibid. p. 508.