- Knowledge of Imam Ali (a.s.) - Ayatullah Sistani as a student of Imam Ali - While people deprived him of government, didn't accept him as caliph, noone ever disputed his level of knowledge - His words, letters, and sermons were of exceptional quality - Nahjul Balagha most famous compilation of his sermons - Throughout time, Sunni scholars have tried to cast doubts upon the authenticity of Nahjul Balagha