Musnad Ahmad 22:42

Abu Ahmad al-Zubayri Muhammad ibn Abdullah narrated to us, Abu Isra'il narrated to us, from Fudayl ibn Amr, from Sa'id ibn Jubayr, from Ibn Abbas, or from al-Fadl ibn Abbas, or from one of them from the other, who said: The Prophet, peace and blessings of Allah be upon him, said: "Whoever intends to perform Hajj, let him hasten, for the stray animal may be lost, the sick person may become ill, and the need may arise."