Abu Dawud Book 4, Hadith Number 1944.
Narated By AbdurRahman Ya’mar ad-Dayli : I came to the Holy Prophet (PBUH) when he was in Arafat. Some people or a group of people came from Najd. They commanded someone (to ask the Prophet about hajj).
So he called the Apostle of Allah (PBUH), saying: How is the hajj done? He (the Prophet) ordered a man (to reply). He shouted loudly: The hajj, the hajj is on the day of Arafah. If anyone comes over there before the dawn prayer on the night of al-Muzdalifah, his hajj will be complete. The period of halting at Mina is three days. Then whoever hastens (his departure) by two days, it is no sin for him, and whoever delays it there is no sin for him.
The narrator said: He (the Prophet) then put a man behind him on the camel. He began to proclaim this loudly.