The hadeeth “Blessed is (Greater) Syria” is a saheeh hadeeth
Question

                How sound is the hadeeth, “Blessed is (Greater) Syria, for the angels of the Most Merciful spread their wings over it”?.
Praise be to Allah.
      This hadeeth is one of the saheeh hadeeths that speak of 
      the virtues of Greater Syria (Bilaad al-Shaam). It was narrated by 
      the great Sahaabi Zayd ibn Thaabit (may Allah be pleased with him) who 
      said: We were with the Messenger of Allah (blessings and peace of Allah be 
      upon him), collecting the Qur’aan from pieces of vellum, and the Messenger 
      of Allah (blessings and peace of Allah be upon him) said: “Blessed is 
      (Greater) Syria.” We said: Why is that, O Messenger of Allah? He said: 
      “Because the angels of the Most Merciful spread their wings over it.” 

    Narrated by al-Tirmidhi (no. 3954); he said: Hasan ghareeb. 
    Also narrated by Imam Ahmad in al-Musnad (35/483, Mu’sasat 
    al-Risaalah edn.), classed as saheeh by the commentators and by Shaykh 
    al-Albaani in al-Silsilah al-Saheehah (no. 503). 

    al-Mubaarakfoori (may Allah have mercy on him) says: 

    “Blessed is (Greater) Syria” means: because it and its people 
    have a good life. 

    “Because the angels of the Most Merciful” this refers to the 
    angels of mercy. 

    “spread their wings over it” means: over the region of 
    (Greater) Syria and its people, protecting them from kufr. This was stated 
    by al-Qaari. Al-Manaawi said: i.e., surrounding it, sending down blessings 
    and warding off calamity and harm. End quote. 

    Tuhfat al-Ahwadhi, 10/315. 

    And Allah knows best.