Thus, there is never a matter on which consensus has been reached without an explanation from the Messenger concerning it. Some people, however, may be unaware of that explanation while knowing of the consensus. They therefore cite the consensus as evidence, just as someone who does not understand a text’s import may cite that text as evidence. This constitutes a second proof alongside the text, like the parables set forth in the Quran. Consensus likewise provides another proof, as when it is said: “This is established by the Book, the Sunnah, and consensus.”

Each of these foundations points to the truth, and they are inseparably connected. Whatever consensus establishes is also established by the Book and the Sunnah. Whatever the Quran establishes has been received from the Messenger; thus, both the Book and the Sunnah are received from him. There is no matter on which consensus has been reached without a text concerning it.

Some people have cited matters on which there is consensus but supposedly no text, such as mudāraba (profit-sharing investment partnerships). This is not so. Rather, mudāraba was widely known among them in the pre-Islamic era, especially among Quraysh, whose predominant occupation was trade. Owners of capital would entrust their wealth to those who conducted business with it. Before his prophethood, the Messenger of Allah, may Allah bless him and grant him peace, travelled on trading journeys with other people’s wealth, including that of Khadījah. Most of the goods in the caravan accompanied by Abū Sufyān were held under mudāraba arrangements with Abū Sufyān and others.

When Islam came, the Messenger of Allah, may Allah bless him and grant him peace, approved this practice. His Companions would travel with other people’s wealth under mudāraba arrangements, and he did not prohibit it. The Sunnah comprises his sayings, actions, and tacit approvals. Since he approved this practice, it was established by the Sunnah.