For it may happen that a man composes a single line of poetry and another produces one just like it, or that a man invents a lie and someone else repeats the very same lie. However, should one compose an elaborate poem—long, varied in style, bound by a single rhyme and metre—custom tells us that no one else will independently create that same poem, word for word and meaning for meaning, at such excessive length. Common experience therefore affirms that the second person must have borrowed it from the first. Likewise, if someone narrates a lengthy account rich in detail and another reproduces it verbatim, then either they colluded, or the latter took it from the former, or else the report is genuine. By this method we recognise the truth of most transmitted material that reaches us through multiple, mutually independent routes, even when no individual route suffices on its own—whether because it is mursal or because its transmitter is weak.

Commentary
The author—may Allah have mercy on him—maintains that when mursal reports come through several chains, and there is no sign of consultation or collusion among their narrators, they are to be deemed sound. He then offers an example: imagine a man informs you of an incident and relates every detail—speech, actions, and, if you wish to add, even the attendees. This man, however, is unreliable in your eyes; you place no trust in his report. Yet another person then comes and recounts the very same incident, and you know that no agreement or prior coordination existed between him and the first. A third, a fourth, and so on follow. Although all these narrators are weak, the fact that each one relates the long story in wording and detail identical to the others makes it highly improbable that the report is fabricated. By contrast, if the incident were minor and one person reported it, then another, and another—each one weak—their concurrence might still fall short of producing certainty, for a single lie can be told, repeated by a second, and echoed by a third.