'Abdullah bin Umar (may Allah be pleased with them) narrates that it was said to Umar bin Khattab (may Allah be pleased with him): "If only you would appoint a successor (caliph)!" He said: "If I appoint a successor, then Abu Bakr (may Allah be pleased with him) also appointed a successor. And if I do not appoint a successor, then the Messenger of Allah (peace and blessings of Allah be upon him) did not appoint a successor." __QUR_N__ Imam Tirmidhi says:
1- There is also an incident mentioned in this hadith. __XREF_N__
2- This hadith is authentic, and it is narrated from Ibn Umar (may Allah be pleased with them) through several chains. __REF_N__

Saeed bin Jumhan says: Safina (may Allah be pleased with him) narrated to us that the Messenger of Allah (peace and blessings of Allah be upon him) said: "Khilafah will remain in my Ummah for thirty years, then after that, kingship will come." Then Safina (may Allah be pleased with him) said to me: Count the Khilafah of Abu Bakr (may Allah be pleased with him), the Khilafah of Umar (may Allah be pleased with him), the Khilafah of Uthman (may Allah be pleased with him), and the Khilafah of Ali (may Allah be pleased with him) 1. The narrator, Hashraj bin Nabatah, says: We found it to be thirty years. Saeed bin Jumhan says: I said to Safina (may Allah be pleased with him): Banu Umayyah think that Khilafah is among them? He said: The Banu Zarqa are lying and wrong, rather, their count is among the worst of kings. Imam Tirmidhi says:
1- This hadith is Hasan (good),
2- Many people have narrated this hadith from Saeed bin Jumhan; we know it only from the narration of Saeed bin Jumhan,
3- In this chapter, there are also ahadith from Umar and Ali (may Allah be pleased with them both) that the Prophet (peace and blessings of Allah be upon him) did not make any bequest regarding Khilafah.