Muwatta Malik 1230

These are the words of a Companion, not of the Prophet ﷺ. The chain is graded on its own terms.

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ عَلِيَّ بْنَ أَبِي طَالِبٍ، قَالَ فِي الْحَكَمَيْنِ اللَّذَيْنِ قَالَ اللَّهُ تَعَالَى ‏{‏وَإِنْ خِفْتُمْ شِقَاقَ بَيْنِهِمَا فَابْعَثُوا حَكَمًا مِنْ أَهْلِهِ وَحَكَمًا مِنْ أَهْلِهَا إِنْ يُرِيدَا إِصْلاَحًا يُوَفِّقِ اللَّهُ بَيْنَهُمَا إِنَّ اللَّهَ كَانَ عَلِيمًا خَبِيرًا‏}‏ إِنَّ إِلَيْهِمَا الْفُرْقَةَ بَيْنَهُمَا وَالاِجْتِمَاعَ ‏.‏ قَالَ مَالِكٌ وَذَلِكَ أَحْسَنُ مَا سَمِعْتُ مِنْ أَهْلِ الْعِلْمِ أَنَّ الْحَكَمَيْنِ يَجُوزُ قَوْلُهُمَا بَيْنَ الرَّجُلِ وَامْرَأَتِهِ فِي الْفُرْقَةِ وَالاِجْتِمَاعِ ‏.‏

Yahya related to me from Malik that he had heard that Ali ibn Abi Talib said about the two arbiters about whom Allah, the Exalted, said,"If you fear a breach between the two, appoint an arbiter from his people, and an arbiter from her people. If they desire to set things aright, Allah will make peace between them, surely Allah is Knowing, Aware," (Sura 4 ayat 35), that the separation and the joining were overseen by the two of them. Malik said, "That is the best of what I have heard from the people of knowledge. Whatever the two arbiters say concerning separation or joining is taken into consideration