Why is understanding the Tabi'un and their followers considered a proof, even though the evidence—such as Allah’s saying: {And the first forerunners [in the faith] among the Muhajireen and the Ansar and those who followed them with good conduct—Allah is pleased with them and they are pleased with Him, and He has prepared for them Gardens beneath which rivers flow, wherein they will abide forever. That is the great attainment} and the Hadith: "Whoever is upon that which I and my companions are upon"—is specific to the authority of the Companions’ understanding?

The consensus of the Companions is a proof, but their disagreement is not a proof, unless no opposing view from them is known. This applies to matters of creed and the fundamentals of religion. The authoritative nature of the Companions' understanding, when they agreed upon something, is not limited to their virtue and characteristics, but encompasses everything by which the authority of consensus is established, and this is not limited to the era of the Companions. Knowing the sayings and actions of the Companions in knowledge and religion is better and more beneficial than knowing the sayings and actions of later generations; because their consensus is infallible, and if they differed, the truth would not lie outside of their views. The methodology of the People of the Sunnah and the Community is to follow the آثار (narrations/traditions) of the Messenger and the predecessors of the Ummah, and the valid consensus is the consensus of the pious predecessors. The proof lies in what the Tabi'un (successors of the Companions) or their followers agreed upon, and the saying or understanding of any one of them is not a proof.