Answered by: Maulana Mujahid Hussain
Please source the original Hadith book this scholar is quoting, and authenticate.
A man from the Khawarij came to Ameer ‘Ali (ra) and said to him: “What is wrong with you, that the people disagreed on you and ‘Uthman, while they agreed on Abu Bakr and ‘Umar?” so ‘Ali answered: “The people agreed on Abu Bakr and ‘Umar when the people were me and ‘Uthman, and they disagreed on me and ‘Uthman when they were like you and your likes [Miraat al-Jinan_ 1/95 مرآةالجنانوعبرةاليقظان
By Abi Muhammad Abdullah bin As-aad al-Yaafi al-Yamani al-Makki]
بسم الله الرحمن الرحي
Unfortunately, I could not find it in any books written by the Salaf Saleheen with a chain of narration. As I result I cannot help you in this regard.
It is mentioned by latter scholars such as Ibn Imaad Hanbali in شذرات الذهب في أخبار من ذهب page 226 volume 1 Dar Ibn khathir print, but without a reference dating back to the time of Ali ( رضي الله عنه )
I encourage you to ask other scholars also. If you manage to find the original source then please share it with us . Jazakallah Kharan
Only Allah Knows best.
Written by Maulana Mujahid Hussain
Checked and approved by Mufti Mohammed Tosir Miah
Darul Hadith Birmingham
This answer was collected from DarulIftaBirmingham.co.uk, which is run under the supervision of Mufti Mohammed Tosir Miah from the United Kingdom.