Hazrat Suwaid bin Ghaflah narrates that Hazrat Ali (may Allah be pleased with him) burned the heretics in the marketplace. When he set fire to them, he said: Allah and His Messenger (peace and blessings be upon him) have spoken the truth. Then he turned back. The narrator says: I followed him, so he turned towards me and asked: Is that Suwaid? I said: Yes! O Commander of the Faithful, I heard you saying something! He said: O Suwaid! Indeed, I am among ignorant people. So when you hear me saying that the Messenger of Allah (peace and blessings be upon him) said, then that is the truth.

Hazrat Abdur Rahman bin Ubaid narrates that Hazrat Ubaid said: There were some people who used to receive annual and monthly stipends and would pray with the people, but in secret they also worshipped idols. These people were brought before Hazrat Ali (may Allah be pleased with him), so he put them in the mosque or in prison. Then he said: O people! What is your opinion about those who receive annual and monthly stipends with you and also worship these idols? The people said: You should kill them. He said: No, but I will deal with them as our father Ibrahim dealt with such people. So he burned them in the fire.

Hazrat Ayyub bin Nu’man narrates that I was present with Hazrat Ali (may Allah be pleased with him) in an open field when a man came and said: O Commander of the Faithful! Indeed, there is a household whose houses contain idols which they worship. So Hazrat Ali (may Allah be pleased with him) stood up and set out until he reached that house. He ordered the people, so they entered and brought out marble statues towards him. Then Hazrat Ali (may Allah be pleased with him) set that house on fire.

Hazrat Makharraq narrates that Hazrat Ali (may Allah be pleased with him) appointed Muhammad bin Abi Bakr as the governor of Egypt. Muhammad wrote a letter to Hazrat Ali (may Allah be pleased with him) and asked him about the Zanaadiqah: some of them worship the sun and the moon, some worship things other than these, and some claim to be Muslims. What is the ruling regarding them? Hazrat Ali (may Allah be pleased with him) wrote a letter and instructed him regarding the Zanaadiqah: kill those among them who claim to be Muslims, and leave the rest; let them worship whomever they wish.

Hazrat Ikrimah narrates that Hazrat Ibn Abbas (may Allah be pleased with them both) received news that Hazrat Ali (may Allah be pleased with him) had captured some heretics and burned them. So he said: As far as I am concerned, I would not punish them with the punishment of Allah, and if I were in that position, I would have killed them. Because of the hadith of the Noble Prophet (peace and blessings be upon him): Whoever changes his religion, kill him.