On return from the Ka’ba, the Prophet(sa) began to receive reports that Christian tribes on the Syrian border, instigated by Jews and pagans, were preparing for an attack upon Medina. He, therefore, despatched a party of fifteen to find out the truth. They saw an army massing on the Syrian border. Instead of returning at once with the report they tarried. Their zeal for expounding Islam got the better of them, but the effect of their well-meaning zeal proved to be the very opposite of what they had wished and expected.
Reviewing events now, we can see that those who, under enemy provocation, were planning to attack the Prophet's(sa) homeland could be expected to behave in no other way. Instead of listening to the exposition, they took out their bows and started raining arrows on this party of fifteen. The party, however, remained unmoved. They received arrows in reply to arguments, but they did not turn back. They stood firm, fifteen against thousands, and fell fighting.
The Prophet(sa) planned an expedition to punish the Syrians for this wanton cruelty, but in the meantime he had reports that the forces which had been concentrating on the border had dispersed. He, therefore, postponed his plans.
The Prophet(sa), however, wrote a letter to the Emperor of Rome (or to the Chief of the Ghassan tribe who ruled Busra in the name of Rome). In this letter, we may presume, the Prophet(sa) complained of the preparations which had been visible on the Syrian border and of the foul and entirely unjust murder of the fifteen Muslims whom he had sent to report on the border situation. This letter was carried by al-Harth(ra), a Companion of the Prophet(sa). He stopped en route at Mauta where he met Shurahbil, a Ghassan chief acting as a Roman official. "Are you a messenger of Muhammad(sa)?" asked this chief. On being told "Yes," he arrested him, tied him up and belaboured him to death. It may quite reasonably be assumed that this Ghassan chief was a leader of the army which had engaged and put to death the fifteen Muslims who had tried only to preach. The fact that he said to al-Harth(ra), "Perhaps you are carrying a message from Muhammad(sa)" shows he was afraid lest the Prophet's(sa) complaint that tribesmen under the Kaiser had attacked the Muslims should reach the Kaiser. He was afraid lest he should have to account for what had happened. There was safety, he thought, in murdering the Prophet's(sa) envoy. The expectation was not realized. The Prophet(sa) got to know of the murder. To avenge this and the earlier murders, he raised a force of three thousand and despatched it to Syria under the command of Zaid bin Haritha(ra), freed slave of the Prophet(sa), whom we mentioned in our account of his life in Mecca. The Prophet(sa) nominated Ja’far ibn Abi Talib as the successor of Zaid(ra), should Zaid(ra) die, and Abdullah bin Rawaha(ra), should Ja’far die. Should Abdullah bin Rawaha(ra) also die, Muslims were to choose their own commander. A Jew who heard this exclaimed, "O Abul Qasim(sa), if thou art a true Prophet(sa), these three officers whom thou hast named are sure to die; for God fulfils the words of a Prophet(sa)." Turning to Zaid(ra), he said,"Take it from me, if Muhammad(sa) is true you will not return alive." Zaid(ra), a true believer that he was, said in reply, "I may return alive or not, but Muhammad(sa) is a true Prophet of God" (Halbiyya, Vol. 3, p. 75).
The following morning the Muslim army set out on its long march. The Prophet(sa) and the Companions went some distance with it. A large and important expedition such as this had never before gone without the Prophet(sa) commanding in person. As the Prophet(sa) walked along to bid the expedition farewell, he counselled and instructed. When they reached the spot where the people of Medina generally bade farewell to friends and relations going to Syria, the Prophet(sa) stopped and said:
I urge you to fear God and to deal justly with Muslims who go with you. Go to war in the name of Allah and fight the enemy in Syria, who is your enemy, as well as Allah's. When you are in Syria, you will meet those who remember God much in their houses of worship. You should have no dispute with them, and give no trouble to them. In the enemy country do not kill any women or children, nor the blind or the old; do not cut down any tree, nor pull down any building (Halbiyya, Vol. 3).
Having said this, the Prophet(sa) returned and the Muslim army marched forward. It was the first Muslim army sent to fight the Christians. When Muslims reached the Syrian border, they heard that the Kaiser himself had taken the field with one hundred thousand of his own soldiers and another hundred thousand recruited from the Christian tribes of Arabia. Confronted by such large enemy numbers, the Muslims half wanted to stop on the way and send word to the Prophet(sa) at Medina. For he might be able to reinforce their numbers or wish to send fresh instructions. When the army leaders took counsel, Abdullah bin Rawaha(ra) stood up, full of fire, and said, "My people, you set out from your homes to die as martyrs in the way of God, and now when martyrdom is in sight you seem to flinch. We have not fought so far because we were better equipped than the enemy in men or material. Our mainstay was our faith. If the enemy is so many times superior to us in numbers or equipment, what does it matter? One reward out of two we must have. We either win, or die as martyrs in the way of God." The army heard ibn Rawaha(ra) and was much impressed. He was right, they said, with one voice. The army marched on. As they marched, they saw the Roman army advancing towards them. So at Mauta the Muslims took up their positions and the battle began. Soon Zaid(ra), the Muslim commander, was killed and the Prophet's cousin Ja’far ibn Abi Talib(ra) received the standard and the command of the army. When he saw that enemy pressure was increasing and Muslims, because of utter physical inferiority, were not holding their own he dismounted from his horse and cut its legs. The action meant that at least he was not going to flee; he would prefer death to flight.
To cut the legs of one's mount was an Arab custom to prevent stampede and panic. Ja’far(ra) lost his right hand, but held the standard in his left. He lost his left hand also and then held the standard between the two stumps pressed to his chest. True to his promise, he fell down fighting. Then Abdullah bin Rawaha(ra), as the Prophet(sa) had ordered, grasped the standard and took over the command. He also fell fighting. The order of the Prophet(sa) now was for Muslims to take counsel together and elect a commander. But there was no time to hold an election. The Muslims might well have yielded to the vastly superior numbers of the enemy. But Khalid bin Walid(ra), accepting the suggestion of a friend, took the standard and went on fighting until evening came. The following day Khalid(ra) took the field again with his crippled and tired force but employed a stratagem. He changed the positions of his men—those in front changed with those in the rear and those on the right flank changed with those on the left. They also raised some slogans. The enemy thought Muslims had received reinforcements overnight and withdrew in fear. Khalid(ra) saved his remnants and returned. The Prophet(sa) had been informed of these events through a revelation. He collected the Muslims in the mosque. As he rose to address them his eyes were wet with tears. He said:
I wish to tell you about the army which left here for the Syrian border. It stood against the enemy and fought. First Zaid(ra), then Ja’far(ra) and then Abdullah bin Rawaha(ra) held the standard. All three fell, one after the other, fighting bravely. Pray for them all. After them the standard was held by Khalid bin Walid(ra). He appointed himself. He is a sword among the swords of God. So he saved the Muslim army and returned (Zad al-Ma’ad, Vol. 1, and Zurqani).
The Prophet's(sa) description of Khalid(ra) became popular. Khalid(ra) came to be known as ‘the sword of God'.
Being one of the later converts, Khalid(ra) was often taunted by other Muslims. Once he and Abdur Rahman bin Auf(ra) quarrelled over something. Abdur Rahman bin Auf(ra) reported against Khalid(ra) to the Prophet(sa). The Prophet(sa) chid Khalid(ra) and said, "Khalid(ra), you annoy one who has been serving Islam from the time of Badr. I say to you that even if you give away gold of the weight of Uhud in the service of Islam, you will not become as deserving of divine reward as Abdur Rahman(ra)"
"But they taunt me," said Khalid(ra), "and I have to reply."
Upon this the Prophet(sa) turned to others and said, "You must not taunt Khalid(ra). He is a sword among the swords of God which remains drawn against disbelievers."
The Prophet's(sa) description came to literal fulfilment a few years later.
On Khalid's(ra) return with the Muslim army, some Muslims of Medina described the returning soldiers as defeatist and lacking in spirit. The general criticism was that they should all have died fighting. The Prophet(sa) chid the critics. Khalid(ra) and his soldiers were not defeatist or lacking in spirit, he said. They were soldiers who returned again and again to attack. The words meant more than appeared on the surface. They foretold battles which Muslims were to fight with Syria.