It is reported about Sayyiduna Abdullah bin Salam (may Allah be pleased with him) that when the people became agitated over the matter of Sayyiduna Uthman (may Allah be pleased with him), he said: "O people! Do not kill this elder; rather, ask him to set matters right. For no nation ever killed its Prophet but that its affairs did not become right until the blood of seventy thousand of them had been shed, and no nation ever killed its Caliph but that its affairs did not become right until the blood of forty thousand of them had been shed." But those people paid no attention to what Sayyiduna Abdullah bin Salam (may Allah be pleased with him) said, and they martyred Sayyiduna Uthman (may Allah be pleased with him). Once Sayyiduna Abdullah bin Salam (may Allah be pleased with him) met Sayyiduna Ali (may Allah be pleased with him) on the road and asked: "Where do you intend to go?" Sayyiduna Ali (may Allah be pleased with him) replied: "I intend to go to the land of Iraq." Sayyiduna Abdullah bin Salam (may Allah be pleased with him) said: "Do not go there; rather, stay by the pulpit of the Messenger of Allah." Some of the companions of Sayyiduna Ali (may Allah be pleased with him) wanted to attack him, but Sayyiduna Ali (may Allah be pleased with him) said: "Leave him, for he is one of us, the People of the House." When Sayyiduna Ali (may Allah be pleased with him) was martyred, Sayyiduna Abdullah bin Salam (may Allah be pleased with him) said to Ibn Ma'qil: "This is the year forty, and at its head there will be a reconciliation. Whenever a nation kills its Prophet, seventy thousand people are killed in exchange for him, and whenever a nation kills its Caliph, forty thousand people are killed in exchange for him."
Al-Tabarani recorded it, and its narrators are the narrators of the Sahih.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب المناقب / 14546