In Sermon (18), Imam Ali (a.s.) criticizes the phenomenon of conflicting opinions among scholars. This sermon reflects a historical context where the Islamic community was witnessing an increase in disagreements among different schools of thought. Imam points out a troubling scenario where one judge gives a ruling based on his personal opinion, only for the same case to be presented to another judge who rules contrary to the first. These judges then gather before the ruler who appointed them, and he validates all their opinions, despite the fact that their God, Prophet, and Book are one.

The Imam questions whether Allah commanded them to differ, or if they are deliberately disobeying Him by doing so. Did Allah leave the religion incomplete, needing their input to complete it? Or do they have a stake in His legislation? These questions underscore that the complete guidance and clarity of the religion is already present in the Quran, and that there should be no contradictions within it.

He cites Quranic verses affirming that nothing has been left out of the Book and that its parts confirm one another without contradiction. This emphasizes that there should not be discord in the religion. Imam Ali (a.s.) states that had the Quran been sent down by anyone other than Allah, there would have been much disagreement within it.

A key moral lesson from this sermon is the necessity for unity and harmony within the Muslim community. While differing opinions are natural, it is essential to remain grounded in the same foundational principles. This sermon teaches us to respect each other's opinions while striving to resolve our differences, and to focus on the fundamental teachings of the religion.