Command of Usamah. It was contended before Abu Bakr with considerable vehemence that in case the expedition was necessarily to be dispatched, there should be a change in the command, and some veteran and seasoned General should be appointed as the Commander instead of Usamah. Umar was commissioned by the companions to put up this demand before the Caliph. Abu Bakr listened attentively to what Umar had to say, and then said: "Umar, Usamah was appointed by the Holy Prophet, and you want me to veto the appointment made by the Holy Prophet. Does it lie in your mouth to take such a recommendation? How can I as the Caliph of the Holy Prophet cancel an order made by the Holy Prophet after due consideration. Go, and tell those who have commissioned you to make this recommendation that this is sheer sacrilege, and as long as Abu Bakr lives he cannot be party to such a sacrilegious act."
This reply considerably embarrassed Umar. He felt sorry for making the recommendation which evoked bitter comments from the Caliph. He returned to Jorf and told all concerned as to what had transpired between him and the Caliph. He was very bitter with those who had chosen him as their spokesman for making a recommendation to the Caliph to make a change in the command.
Departure of the army. Abu Bakr directed the army to depart on its mission. Abu Bakr went to Jorf to bid farewell to the army and addressed them in the following terms: "See that you avoid treachery. Depart not in any wise from the right. Do not mutilate any one. You should not kill children, women or old men. Do not injure the date palm; do not burn it. Do not cut down any tree wherein there is food for men and beasts. Do not slay the flocks of herds of camels save for needful sustenance. You may eat of the meat that the men of the land may bring to you in their vessels, making mention thereon of the name of Allah. Do not molest the monks in the churches, and leave them to themselves. Now march forward in the name of God. Fulfil the mission entrusted to you. May Allah protect you from sword and pestilence!"
Abu Bakr walked for some distance alone with the army to see it depart. Usamah who was riding on horseback prayed that he should be permitted to dismount, or the Caliph should also ride on a horse. Abu Bakr said: "No. neither should you dismount, nor would I mount a horse. You ride in the service of God, and I shall account to God for these steps that I take in your company."
The Campaign. The army of Usamah left Jorf towards the close of June 632 C.E. After a ten days march, the Muslim army penetrated into the region of Wadi-al-Qara, and fell on Banu al-Qidzah and other border tribes. Usamah rode on his father's horse 'Sabah". He sought the person who had killed his father at the battle of Mutah, and having recognized him put him to the sword. The Byzantine forces avoided confrontation with the Muslim force, and the border tribes left to themselves were no match for the Muslim forces. They were thoroughly discomfited, and hastened to offer allegiance to the authorities at Madina. The expedition proved to be a great success. It secured the safety of the frontier with the Byzantines and averted the threat of any attack from the Byzantines. The success that attended the Muslim arms made the unruly tribes realize that Islam was not dead with the death of the Holy Prophet, and that the Muslims were strong enough to meet all emergencies. Usamah's army returned to Madina, in August 632 C.E. laden with considerable booty. On return to Madina, the army of Usamah was given a tumultuous welcome.