It is narrated from Hazrat Qutbah bin Malik (may Allah be pleased with him) that once a disrespectful remark about Hazrat Ali (may Allah be pleased with him) came from the tongue of Hazrat Mughirah bin Shu'bah (may Allah be pleased with him). So Hazrat Zaid bin Arqam (may Allah be pleased with him) said to him, "Do you know that the Holy Prophet (peace and blessings of Allah be upon him) forbade speaking ill of the dead? Then why are you saying such things about Hazrat Ali (may Allah be pleased with him) when he has passed away?"