Muwatta Malik: Hajj — Amir al-muminin, we made a mistake in our reckoning and we thought that today… (Hadith No. 862)

Malik related to me from Nafi from Sulayman ibn Yasar that Habbar ibn al-Aswad arrived on the day of sacrifice while Umar ibn al-Khattab was sacrificing his animal and said, "Amir al-muminin, we made a mistake in our reckoning and we thought that today was the day of Arafa." Umar said, "Go to Makka, you and whoever else is with you, and do tawaf and sacrifice your animal if you have one with you. Then shave or cut your hair and return home. Then, in another year, do hajj and sacrifice an animal, and if you cannot find one, fast three days on hajj and seven when you return home." Malik said, "Someone who intends to do hajj and umra together and then misses the hajj must do hajj again in another year, doing hajj with umra, and offer two sacrificial animals, one for doing the hajj with umra, and one for the hajj that he has missed

Explanation:

Reference: Muwatta Malik: Hajj, Hadith No. 862