In the third year after Hijrah and the month of Shawwaal, people of Madinah heard that the enemy of Islam, Abu Sufyaan, was approaching their city with an army of three thousand highly skilled soldiers from all over Arab. The Meccans intended to attack Madinah with an army of camels loaded with weapons and two hundred of the finest war horses under the leadership of their (then non-believer) commander, Khalid Bin Waleed (ra).
The Holy Prophet (sas) immediately instructed Muslims to prepare for war. After consulting with his companions, he decided to fight the war outside Madinah. When women came to know about the departure of the Muslim army, a group of them including Hazrat Umme Ummaarah (ra) approached the Holy Prophet (sas) and requested his permission to join the fight. They wished to participate in the war to help the wounded and give them water.