As for the battalions that the Prophet (a.s.) had sent to some districts and villages, the purpose of them was to show the power and authority of Islam there and not to let those villages join the enemies of Islam. From the other goals, it was to spread the high principles and values among those people and to liberate them from idolatry and the bad habits of the pre-Islamic age of ignorance.
Anyhow, we mention here the battalions that the Prophet (a.s.) sent here and there and entrusted their leaderships to some of his companions. They were thirty-eight as the following:
1. The battalion of Zayd bin Haritha
The Prophet (a.s.) sent Zayd bin Haritha on a battalion from the Muslim army to attack a trading caravan of Quraysh headed by Abu Sufyan. Zayd with his battalion could find and arrest the caravan with all the goods, whereas all the men of the caravan ran away. The purpose of this attack was to weaken the power of the main enemy of Islam; the tribe of Quraysh.
2. The battalion of Khalid
The Prophet (a.s.) sent some battalions to the villages around Mecca inviting their people towards Allah alone. He sent a battalion under the leadership of Khalid bin al-Waleed to the Banu Juthaymah to invite them to Islam and not to fight them. When Khaild arrived there, he ordered the people of Juthaymah to put their arms aside. Jahdam, a man from the tribe, suspecting Khalid, said to his tribe, “How bad it is to you, O Banu Juthayma! It is Khalid. By Allah, there is nothing after the putting aside of arms except capturing, and there is nothing
 As-Seera an-Nabawiyyah by ibn Hisham, vol. 4 p. 284.
after the capturing except beheading. By Allah, I will not put my weapon aside.”
Some men of his tribe denied him and said, “O Jahdam, do you want to shed our bloods? The people have turned Muslims and put their arms aside. The war has been cancelled and people have felt secure.”
They insisted on him until they could take off his sword. When they all put aside their arms, Khalid ordered them to be tied, and then he killed many of them by the sword. When the news came to the Prophet (a.s.), he became very angry and felt great pain. He raised his hands towards the heaven and said, “O Allah, I am free to you from what Khalid has done.”
Then, the Prophet (a.s.) sent for Imam Ali (a.s.) and ordered him to go to the Banu Juthaymah to repair the affairs. Imam Ali (a.s.) set out carrying with him monies which the Prophet (a.s.) had given to be paid as blood-money of the killed ones. Imam Ali (a.s.) paid to and recompensed them for everything even for a dog’s broken drinking vessel. Nothing of shed blood or damaged property remained except that Imam Ali (a.s.) paid money for it. Some money remained with the Imam, but he gave it to them saying, “I give you the remainder of this money as a precaution for the messenger of Allah from what he does not know and what you do not know.”
Imam Ali (a.s.) went back to the Prophet (a.s.) and told him of what happened. The Prophet (a.s.) thanked him and said, “You have done well and right.” Then the Prophet (a.s.) raised his hands towards the heaven and said, “O Allah, I am free to you from what Khalid has done.” He said that three times.
 As-Seera an-Nabawiyyah by ibn Hisham, vol. 2 p. 429-430.
This event shows that Khalid did not care for the Islamic morals. He did not regard any covenant. In fact he was eager to shed bloods. His famous story with Malik bin Nuwayrah was another evidence that very clearly confirms this fact.
3. The battalion of Abdullah bin Rawaha
The Prophet (a.s.) sent Abdullah bin Rawaha with thirty horsemen to Yusayr bin Rizam the Jew. The Prophet (a.s.) had been informed about the evil and the plotting of this villain Jew who was gathering people in order to fight against the Prophet (a.s.) and his companions. When Abdullah bin Rawaha met Yusayr, he said to him, “The messenger of Allah has sent us to you (to tell you) that he has decided to appoint you the wali over Khaybar.” After insistence, he responded and went with the Muslims accompanied by thirty men from his people like the number of the Muslims accompanying Abdullah bin Rawaha. When they arrived in Qarqarat Niyar (six miles from Khaybar), Yusayr regretted what he had done, and so he fell down to take the sword of Abdullah bin Rawaha who noticed that and he struck Yusayr’s leg and cut it. Yusayr hit Abdullah with a stick that was in his hand and he wounded his head. Then every Muslim attacked the Jew that was before him. All the Jews were killed except one who could run away, whereas no one of the Muslims was killed. When Abdullah came back, the Prophet (a.s.) saw the wound in his head. He treated the wound with his saliva and it got well.
4. The battalion of Basheer bin Sa’d
The Prophet (a.s.) sent Basheer bin Sa’d with thirty horsemen to the Banu Murrah in Fadak who fought him and killed all the men with him. Basheer was patient in fighting them. He fought
 As-Seera an-Nabawiyyah by ibn Hisham, vol. 3 p. 418.
courageously until he could escape them safely and go back to Medina.
Then, the Prophet (a.s.) sent to them Ghalib bin Abdullah with some great companions among whom was Usamah bin Zayd and ibn Mas’ud. Usamah fought against Mardas bin Nehik, and when he was able to kill him, Mardas said, “There is no god but Allah”. However, Usamah did not care for that and he killed the man. The companions blamed Usamah for that. The Prophet (a.s.) was too much distressed for that and he said to Usamah, “O Usamah, who is to you without ‘there is no god but Allah’?” Usamah felt great regret for the great sin he committed.
5. The battalion of Abu Hadrad
Rifa’ah bin Qays and some men from the Banu Jusham bin Mo’awiya camped in a forest trying to gather some other people in order to fight against the Prophet (a.s.) and his followers. The Prophet (a.s.) sent for Abu Hadrad and other two Muslims and ordered them to deal with the trouble of Rifa’ah. They set out until they were near the camp of Rifa’ah and his men. In the night, Abu Hadrad could kill Rifa’ah, and then he with his two companions went back to the Prophet (a.s.).
6. The battalion of Amr bin al-Aas
The Prophet (a.s.) sent Amr on the head of a battalion to mobilize the Arab tribes towards Sham. No fight took place during this expedition. Its task was just to call people to attack Sham.
 As-Seera an-Nabawiyyah by ibn Hisham, vol. 3 p. 419.
 Ibid., p. 422.
7. The battalion of Zayd bin Harithah
Zayd bin Harithah attacked, with a battalion, Wadi al-Qura in which there was a people from the Banu Fazarah. In this fight, Zayd was wounded. He took an oath that he would not sleep with his wife except after defeating the Banu Fazarah. He went back to the Prophet (a.s.) who made him the leader of an army that marched again towards the Banu Fazarah who were killed in this battle and the rest of them were taken prisoners.
The mentioned above are some of the military tasks that the Prophet (a.s.) had sent to guide people to Islam or to defeat some groups of polytheists or unfaithful powers that were hostile to Islam and Muslims. There were other military tasks that we see it is not necessary to mention them all here. Ibn Hisham mentions in his Seera that those tasks were thirty-eight ones in the form of battalions the Prophet (a.s.) had sent here and there under the leadership of some of his companions.
 As-Seera an-Nabawiyyah by ibn Hisham, vol. 3, p. 617.
 Ibid., vol. 2 p. 136.