Narrated Abu Bakrah: The Prophet ﷺ gave a sermon during his hajj and said: Time has completed a cycle and assumed the form of the day when Allah created the heavens and the earth. The year contains twelve months of which four are sacred, three of them consecutive, viz. Dhul-Qa'dah, Dhul-Hijjah and Muharram and also Rajab of Mudar which comes between Jumadah and Sha'ban.
Hadith Referenceسنن ابي داود / كتاب المناسك / 1947
Hadith Gradingالألبانی:صحيح | زبیر علی زئی:إسناده صحيح، صحيح بخاري (4406) صحيح مسلم (1679), انظر الحديث الآتي (1948)
The aforesaid tradition has also been transmitted by Abu Bakrah through a different chain of narrators. Abu Dawud said: Ibn 'Awn has mentioned his (Abu Bakrah's) name and narrated this tradition: From Abdur-Rahman bin Abi Bakrah on the authority of Abu Bakrah.
Hadith Referenceسنن ابي داود / كتاب المناسك / 1948
Hadith Gradingزبیر علی زئی:صحيح بخاري (4406) صحيح مسلم (1679)