Amina Inloes, Amina Inloes is originally from the US and has a PhD in Islamic Studies from the University of Exeter on Shi'a hadith. She is the program leader for the MA Islamic Studies program at the... Answer updated 3 years ago

Although this statement is popularly attributed to Imam 'Ali (A), as far as I know, there is no source clearly relating this source from Imam 'Ali (A).

However, if I recall correctly, it is attributed to him (without a chain of narration or the like) by Ibn Abi al-Hadid in Sharh Nahj al-Balaghah.

It is also attributed to Plato by some other classical Arab authors.

Allah knows best.