Muwatta Malik 320
موطأ مالك#320SahihThese are the words of a Successor — the generation after the Companions — not of the Prophet ﷺ.
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ رَبِيعَةَ بْنِ أَبِي عَبْدِ الرَّحْمَنِ، أَنَّ مُحَمَّدَ بْنَ عَمْرِو بْنِ حَزْمٍ، كَانَ يُصَلِّي فِي الْقَمِيصِ الْوَاحِدِ .
Yahya related to me from Malik from Rabia ibn Abi Abd ar-Rahman that Muhammad ibn Amr ibn Hazm used to pray in a single long shirt
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Salim al-HilaliMaqtu Sahih
In-book reference: 8:34