Al-Matalib al-'Aliyah 1134 — The sanctuary of Makkah

It is narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) delivered a sermon (on the occasion of the Farewell Pilgrimage), and (during the address) he said: "O people, time has turned round and returned to its original state, as it was on the day Allah Almighty created the heavens and the earth. And indeed the number of months with Allah is twelve months in the Book of Allah [Surah al-Tawbah: 36]; four of them are sacred: (one) the Rajab of the tribe of Mudar, which is between Jumada al-Akhirah and Sha'ban, and Dhu al-Qa'dah, Dhu al-Hijjah and Muharram. And al-nasi' (shifting the months back and forth) is only an increase in disbelief by which those who disbelieve are led astray [Surah al-Tawbah: 37]. This was because they would make Safar lawful one year and declare it sacred another year, and they did the same with Muharram; and this nasi' was from Satan." The hadith further states that he (peace and blessings be upon him) asked: "What day is this?" The Companions said: It is a sacred day. He (peace and blessings be upon him) asked: "What month is this?" They said: It is a sacred month. He (peace and blessings be upon him) asked: "What city is this?" They said: It is a sacred city (Makkah). Then he (peace and blessings be upon him) said: "Indeed, Allah Almighty has made your blood, your property and your honour sacred to you, just as the sanctity of this day of yours, in this month of yours, in this city of yours. Beware! There will be no prophet after me, and there will be no (new) nation after you. Take heed! Let the one who is present convey (my message) to the one who is absent." Then he (peace and blessings be upon him) raised his blessed hands and said three times: 'Allahumma ishhad, Allahumma ishhad' (O Allah, be witness; O Allah, be witness).
Imam Abd bin Humayd narrated it at length through the chain of Abu Bakr bin Abi Shaybah, and Imam Abu Ya'la also related it through another route via Musa bin Ubaydah.