Shafi'i said: Some asked me: I have understood your doctrine concerning God's commands and His Apostle's orders that he who obeys God obeys His Apostle, [for] God has imposed [on men] the duty of obeying His Apostle, and that the proof for what you held has been established that it would be unlawful for a Muslim who has known the Book [of God] and the sunna [i.e., Hadith tradition of the Prophet] to give an opinion at variance with either one, for I know that this [i.e., acceptance of the Book and the sunna] is a duty imposed by God. But what is your proof for accepting the consensus of the public [on matters] concerning which no explicit command of God nor any [sunna] related on the authority of the Prophet is to be found? Do you assert, with others, that the consensus of the public should always be based on an established sunna even if it were not related [on the authority of the Prophet]?
[Shafi'i] replied: That on which the public are agreed and which, as they assert, was related from the Apostle, that is so. As to that which the public do not relate [from the Prophet], which they may or may not relate as a tradition from the Prophet, we cannot consider it as related on the authority of the Prophet-because one may relate only what he has heard, for no one is permitted to relate [on the authority of the Prophet] information which may or may not be true. So we accept the decision of the public because we have to obey their authority, and we know that wherever there are sunnas of the Prophet, the public cannot be ignorant of them, although it is possible that some are, and we know that the public can neither agree on anything contrary to the sunna of the Prophet nor on an error.
He asked: What is the meaning of the Prophet's order to follow the community?
[Shafi'i] replied: When the community spread in the lands [of Islam], nobody was able to follow its members who had been dispersed and mixed with other believers and unbelievers, pious and impious. So it was meaningless to follow the community [as a whole], because it was impossible [to do so], except for what the [entire] community regarded as lawful or unlawful [orders] and [the duty] to obey these [orders].
He who holds what the Muslim community holds shall be regarded as following the community, and he who holds differently shall be regarded as opposing the community he was ordered to follow. So the error comes from separation: but in the community as a whole there is no error concerning the meaning of the Qur'an, the sunna, and analogy.
by Abu Abdullah Muhammad ibn Idrīs al-Shafi'i (767-820)