Sunan Abi Dawud 1947
سنن أبي داود#1947SahihNarrated AbuBakrah: 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
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Zubair Ali ZaiIsnaad Sahih Sahih Bukhari (4406) Sahih Muslim (1679)
In-book reference: 11:227