While the Muslims were at Fahl, sensing the weak defense of Damascus, Emperor Heraclius sent an army to re-capture the city. This army, however, could not make it to Damascus and was intercepted by Abu Ubaidah and Khalid on their way to Emesa. The army was destroyed in the battle of Maraj-al-Rome and the second battle of Damascus.
This sequence of events occurred when the Muslims were stationed at Fahl and became aware of the weakened defenses of Damascus. Emperor Heraclius responded by sending an army to retake the city, but it was intercepted by Abu Ubaidah and Khalid on their way to Emesa, leading to a decisive defeat in the Battle of Maraj-al-Rome and the Second Battle of Damascus.