وَحَدَّثَنِي مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ قُهْزَاذَ، مِنْ أَهْلِ مَرْوَ، قَالَ: سَمِعْتُ عَبْدَانَ بْنَ عُثْمَانَ، يَقُولُ: سَمِعْتُ عَبْدَ اللَّهِ بْنَ الْمُبَارَكِ، يَقُولُ: «الْإِسْنَادُ مِنَ الدِّينِ، وَلَوْلَا الْإِسْنَادُ لَقَالَ مَنْ شَاءَ مَا شَاءَ».
Translation: Muḥammad b. ʿAbd Allāh b. Quhzādh transmitted through ʿAbdān b. ʿUthmān that ʿAbd Allāh b. al-Mubārak said: “Isnād belongs to religion; without isnād anyone could say anything.”
A chain makes the claim of attribution examinable: contact and transmission can be investigated, narrators assessed and variants compared. The mere presence of names in a chain is not itself proof of authenticity.