Musnad Ahmad 988:3

'Isam ibn Khalid and 'Ali ibn 'Ayyash narrated to us, they said: Huraiz narrated to us, from Sulayman ibn Samir, from Ibn Hawalah al-Azdi—and he was one of the companions of the Messenger of Allah, peace and blessings of Allah be upon him—from the Prophet, peace and blessings of Allah be upon him, that he said: "There will be mobilized armies: a Sham army, a Yemen army, and an Iraq army." Allah knows best with which of them He began. "But you must go to Sham. Beware, you must go to Sham. Beware, you must go to Sham. Whoever dislikes that, let him go to his Yemen and let him drink from its ponds, for Allah, the Mighty and Majestic, has guaranteed for me Sham and its people."