It is narrated from Hazrat Abdullah bin Hawalah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Whoever is saved from three things is indeed saved (he said this three times): my death, the Dajjal, and the killing of a rightly guided caliph who remains firm upon the truth."
Hadith Referenceمسند احمد / مسند الشاميين / 17003
Hadith Gradingحکم دارالسلام:حديث صحيح ، ليس هذا الحديث بمصر من حديث يحيى بن أيوب، لكنه توبع