It is narrated from Dhar', Abu Talhah al-Khawlani, that the Messenger of Allah (peace and blessings be upon him) said: "There will be four armies. Hold fast to al-Sham, for Allah, the Mighty and Majestic, has guaranteed al-Sham (and its people) for me."
Hadith Referenceالمعجم الكبير للطبراني / باب الذال / 4207