A magnified image of the prominent danger threatening the Muslims life was carried to them by the Nabateans who brought oil from Ash-Sham to Madinah. They carried news about Heraclius’ preparations and equipment of an enormous army counting over forty thousand fighters besides Lukham, Judham and other tribes allied to the Byzantines. They said that its vanguard had already reached Al-Balqâ’. Thus was the grave situation standing in ambush for the Muslims. The general situation was aggravated seriously by other adverse factors of too much hot weather, drought and the rough and rugged distance they had to cover in case they decided to encounter the imminent danger.
The Messenger of Allâh’s (peace be upon him) concept and estimation of the situation and its development was more precise and accurate than all others. He thought that if he tarried or dealt passively with the situation in such a way that might enable the Byzantines to paddle through the Islamic controlled provinces or to go as far as Madinah, this would — amid these circumstances — leave the most awful impression on Islam as well as on the Muslims’ military credibility.
The pre-Islamic beliefs and traditions (Al-Jahiliyah) which were at that time dying because of the strong decisive blow that they had already had at Hunain, could have had a way to come back to life once again in such an environment. The hypocrites who were conspiring against the Muslims so that they might stab them in the back whereas Byzantines would attack them from the front. If such a thing came to light and they succeeded in their evil attempts, the Prophet and his Companions’ efforts to spread Islam would collapse and their profits which were the consequences of successive and constant fights and invasions would be invalidated. The Messenger of Allâh (peace be upon him) realised all that very well. So — in spite of the hardships and drought that Muslims were suffering from — the Prophet (peace be upon him) was determined that the Muslims should invade the Byzantines and fight a decisive battle at their own borders. He was determined not to tarry at all in order to thwart any Roman attempt to approach the land of Islam.
When the Messenger of Allâh (peace be upon him) had made up his mind and took his final decision, he ordered his Companions to get ready for war and sent for the Makkans and the other Arab tribes asking for their assistance.
Contrary to his habit of concealing his real intention of the invasion by means of declaring a false one, he announced openly his intention of meeting the Byzantines and fighting them. He cleared the situation to his people so that they would get ready, and urged them to fight in the way of Allâh. On this occasion a part of Surat Bara’a (Chapter 9 — The Repentance) was sent down by Allâh, urging them to steadfastness and stamina.
On the other hand, the Messenger of Allâh (peace be upon him) cherished them to pay charities and to spend the best of their fortunes in the way of Allâh.
No sooner had the Muslims heard the voice of the Messenger of Allâh (peace be upon him) calling them to fight the Byzantines than they rushed to comply with his orders. With great speed they started getting ready for war. Tribes and phratries from here and there began pouring in Madinah. Almost all the Muslims responded positively. Only those who had weakness at their hearts favoured to stay behind. They were only three people. Even the needy and the poor who could not afford a ride came to the Messenger of Allâh (peace be upon him) asking for one so that they would be able to share in the fight against the Byzantines. But when he said:
“...‘I can find no mounts for you’ they turned back while their eyes overflowing with tears of grief that they could not find anything to spend (for Jihad).” [9:92]
The Muslims raced to spend out money and to pay charities to provide this invasion. ‘Uthman, for instance, who had already rigged two hundred, saddled camels to travel to Ash-Sham, presented them all with two hundred o(of gold) as charity. He also fetched a thousand dinars and cast them all into the lap of the Messenger of Allâh (peace be upon him), who turned them over and said: “From this day on nothing will harm ‘Uthman regardless of what he does.” Again and again ‘Uthman gave till his charity toped to nine hundred camels and a hundred horses, besides the money he paid.
Abdur Rahman bin ‘Awf, on his side, paid two hundred silver ounces, whereas Abu Bakr paid the whole money he had and left nothing but Allâh and His Messenger as a fortune for his family. ‘Umar paid half his fortune. Al-‘Abbas gifted a lot of money. Talhah, Sa‘d bin ‘Ubadah and Muhammad bin Maslamah, gave money for the welfare of the invasion. ‘Asim bin ‘Adi, on his turn, offered ninety camel-burdens of dates. People raced to pay little and much charities alike. One of them gave the only half bushel (or the only bushel) he owned. Women shared in this competition by giving the things they owned; such as musk, armlets, anklets, ear-rings and rings. No one abstained from spending out money, or was too mean to grant money or anything except the hypocrites:
“Those who defame such of the believers who give charity (in Allâh’s cause) voluntarily, and those who could not find to give charity (in Allâh’s cause) except what is available to them, so they mock at them (believers).” [9:79]