Mu’ta is located to the south of Lake Galilee, 50 kilometers from the city of Jerusalem. At the beginning of the eighth year after the Emigration (629 AD), Prophet Muhammad sent Harith ibn 'Umayr with a letter of invitation to Islam to the provincial governor of Busra, under the Byzantine Empire. As the Prophet’s envoy passed through the lands of the Ghassanid Christian King, Shurahbil ibn ‘Amr, he was killed by the latter. Harith ibn 'Umayr is the only envoy of Prophet Muhammad to have been killed. As a result of this blatant violation of international law stipulating immunity for emissaries and envoys, Prophet Muhammad organized a force of 3000 and appointed Zayd ibn Harith as commander. He then commanded that Ja’far ibn Abi Talib would take command in the event of Zayd’s being killed, 'Abd Allah ibn Rawaha would assume command if Ja’far was killed, and if he too were killed, then the Muslims would elect a commander from among themselves. The Prophet also ordered that when the place where the envoy was killed was reached, the people there would first be invited to Islam and if they accepted, they were not to fight. He also commanded them not to touch children, women, the elderly and those retreating to monasteries, not to inflict damage on the date gardens, not to cut down trees, and not to destroy buildings.
The Muslim army reached Mu’ta via Wadi al-Qura' and Ma'an. Here, they confronted a large army of 100,000 or 200,000 according to accounts, including Byzantine forces under the general command of Theodorus, and Christian Arab tribes led by Shurahbil ibn ‘Amr (Jamadi al-Awwal/September 629). When Zayd ibn Harith was martyred at the battle’s onset, the standard was taken by Ja’far ibn Abi Talib. Losing his right hand, Ja’far held the standard with his left, and when that too was cut off, he held the standard between his arms and his chest, but was however martyred at the stroke of a spear. When 'Abd Allah ibn Rawaha who thereafter assumed command was also martyred, the standard was entrusted to Khalid ibn Walid. According to narration, at the time in which these events were unfolding at Mu’ta, Prophet Muhammad – sitting in the Prophet’s Mosque with his Companions – related to them the developments on the battlefield, recounting the fall of the commanders one after the other. When command was given to Khalid ibn Walid, he said: “Then the flag was taken by a Sword amongst the Swords of God (i.e. Khalid) and God made them (i.e. the Muslims) victorious." Changing the troops on the right flank to the left, and the left flank to the right, bringing forth the rearguard, and sending the vanguard troops to the rear, Khalid gave the impression that reinforcements had arrived. While slowly retreating, he inflicted as much damage on the Byzantine army as he could, occasionally gaining war spoils, and succeeded in bringing the Muslim army safely back to Madina.
The Muslims lost fifteen of their men at Mu’ta. Prophet Muhammad shed tears for these martyrs, but forbade lamenting and wailing; he also directed relatives and those close to the bereaved families to take food and provide assistance with their tasks for three consecutive days. He himself sent food to the house of his paternal cousin Ja’far for three days and later took Ja’far’s children in his care, assuming their upbringing and care.
The Muslim troops at Mu’ta fought with resolve the enemy much greater in strength than them. Six months prior to the battle of Mu’ta – during the time at which Prophet Muhammad visited Makka to make up for the minor pilgrimage that they could not perform earlier – Khalid ibn Walid had embraced Islam, had participated in battle alongside the Muslims for the first time and, praised by the Prophet for the great valor he displayed in battle, was given the title “Sword of God”. As he himself narrates: “On the day (of the battle of) Mu'ta, nine swords were broken in my hand, and nothing was left in my hand except a Yemenite sword of mine.” Also participating in the battle, ‘Abd Allah ibn ‘Umar and his friends stated that they counted more than fifty sword, arrow and spear wounds on Ja’far ibn Abi Talib’s chest. The Prophet announced that Ja’far would be two-winged in Paradise in return for the two hands he had lost; hence thereafter, he was called “Ja’far al-Tayyar” (the Great Flier).
Despite its status as a military expedition in which Prophet Muhammad did not take part (sariyya), the Battle of Mu’ta has been referred to in certain sources as a ghazwa (the term given to military expeditions in which the Prophet took part) most probably because of its size, importance, and due to its being a pitched battle.
With this battle, the Muslim army confronted one of the greatest empires of the day, the Byzantine Army, for the very first time. The Muslim army’s retreat to Madina without greater losses in the face of an army much more superior in terms of numbers and strength must be regarded as a success. Professor Mustafa Fayda explains the importance of this battle from the perspective of the Muslims as follows: “By means of the Battle of Mu’ta, Khalid and the Muslims gained an opportunity to familiarize themselves much more closely with the Byzantine forces, their style of warfare, their tactics and their weapons. The benefit of this lived experience is to be seen in the battles fought against the Byzantine army, first and foremost the Battle of Yarmuk. Moreover, Arabs in the regions of Syria and Palestine witnessed the Muslims’ belief, bravery, and chivalry, and became acquainted with this new religion and its adherents.” (See, Mustafa Fayda, Allah’ın Kılıcı Halid b. Velid (The Sword of God: Khalid ibn Walid), p. 168.)