Hazrat Makharraq (may Allah have mercy on him) narrates that Hazrat Ali (may Allah be pleased with him) sent Muhammad bin Abi Bakr as the governor over the people of Egypt. So he wrote a letter to Hazrat Ali (may Allah be pleased with him) and asked about the Zindiqs, some of whom worshipped the sun and the moon, and some of whom worshipped other things, and some claimed to be Muslims. Hazrat Ali (may Allah be pleased with him) wrote a letter to him and ordered regarding the Zindiqs that whoever claims to be a Muslim among them, kill him, and leave all the rest; let them worship whatever they wish.