Musnad Ahmad 739
It was narrated that ‘Ali (رضي الله عنه) said:
The Messenger of Allah (ﷺ)  said: “If I were to appoint anyone to a position of authority without consulting (the believers), I would have appointed Ibn Umm `Abd (`Abdullah bin Mas`ood).`
حَدَّثَنَا وَكِيعٌ، عَنْ سُفْيَانَ، عَنِ أَبِي إِسْحَاقَ، عَنِ الْحَارِثِ، عَنْ عَلِيٍّ، رَضِيَ اللَّهُ عَنْهُ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ لَوْ اسْتَخْلَفْتُ أَحَدًا عَنْ غَيْرِ مَشُورَةٍ لَاسْتَخْلَفْتُ ابْنَ أُمِّ عَبْدٍ‏.‏