The Quraish had begun grand-scale preparations to attack Medina. The trade caravan which had gone to Syria that year headed by Abu Sufyan was extraordinarily equipped. Every Quraishite put all his savings in that caravan, and it was decided that whatever the profit accrued that year, it would not be given to the traders but would be spent on arms, horses, and other items of war to fight the Muslims of Medina.
This news did cause much anxiety in Medina. As Abu Sufyan was returning from Syria, he feared that the Muslims might intercept his trade caravan. He sent a messenger well in advance to inform the leaders of the Quraish of his fears. Upon receiving the message, a well-equipped army of one thousand Meccans marched towards Medina under the command of Abu Jahl.
They had reached Badr (200 miles from Mecca and 80 miles from Medina) when news came that the trade caravan was passing just three miles on the seaside from the Quraishites' camp, and that it had not encountered any attack from the Muslims yet. But since the Meccans were so eager on giving battle to Muhammad (s.a.w.a.) and his followers, they decided to proceed towards Medina anyway. After all, was not the objective of sending such a trade caravan this very battle?! So, why should they go back to Mecca when they had one thousand well-equipped warriors among them who were sufficient to teach the Muslims a lesson? They camped at the stream of Badr.
Now let us see what was happening in Medina. When news came that the trade caravan was coming from Syria (on the north side) and that the Meccan army was marching towards Medina (from the South), the Muslims thought that they would be crushed between these two enemy groups.
Now, there were two alternatives before the Muslims in Medina: to either save themselves from being overwhelmed by the Meccans with all their resources from the rich Syrian trade, or make another option (one which had the least danger for the time being and which also promised a rich booty): fall upon the Quraishi caravan returning from Syria richly laden and led by Abu Sufyan with only 40 not so well-armed men. From a worldly point of view, this latter course was the safest and the most lucrative, and many Muslims preferred it. The other alternative, which was actually adopted on the recommendation of the Prophet as guided by God, was to leave the booty alone and to march out boldly against the well-armed and well-equipped Quraishite army of 1,000 men coming from Mecca.
This situation is described in the following ayats of the Qur'an:
Just as your Lord caused you (O Prophet!) to go forth from your house with the truth, though a party of the believers was averse, they disputed with you about the truth after it had become clear, (and they went forth) as if they were being driven to death while they looked (at it). And when Allah promised you one of the two parties that it shall be yours, and you loved that the one not armed should be yours, and Allah desired to manifest the truth of what was true by His words and to cut off the root of the unbelievers. He may manifest the truth of what was true and show the falsehood of what was false, even though the guilty ones disliked it. (Qur'an, 8:5-8)
These verses clearly show that the Meccan army was already on its way long before the Muslims came out of Medina to defend themselves. Also, they clearly show that although some Muslims desired to avoid the Meccan army and to attack the trade caravan, that idea was not accepted and that the decided aim and objective of their march was to fight the Meccan army which was already on its way.
This clearly belies the vicious and mischievous propaganda of Western writers who claim that the Prophet had intended to attack the trade caravan of the Quraish and that the Quraish had come out only to protect their caravan. The verses of the Qur'an are the only contemporary record of the events of Badr. If there is any writing by anyone, which goes against this authentic narrative, it must be thrown out of the window.
You may wonder why the enemies of Islam labor so much to present this battle of Badr as one in which the Quraishites (poor souls!) were aiming just to protect their trade caravan. The reason is this: It was the first battle between the Quraishites and the Muslims, and if the responsibility of this first battle is laid on the heads of the Muslims, then all subsequent battles could be portrayed as being the continuation of this battle and, thus, the Holy Prophet could be presented as a warrior prophet who by his plundering designs compelled the "peace-loving" Meccans to fight!
Anyhow, let us go back to our narrative. The Meccan army was in control of the stream of Badr, and the ground of their campsite was of firm clay. Contrarily, the Muslims were far from the stream and thus experienced difficulty in finding water. To make matters worse, many Muslims had nocturnal discharge while asleep and became "unclean" (najis). And the ground under them was sandy which was likely to prevent fast running during the battle.
God helped them by sending rain which provided them with water enough for their needs and made the sandy ground firm for them, while the firm clay of the Meccans' side became muddy, making their stand and maneuvers difficult.
Referring to this, Allah says in the Qur'an:
(Remember) when He caused drowsiness to fall on you as a security from Him and sent down upon you water from the cloud so that He might thereby purify you and take away from you the uncleanness of Satan, so that He might fortes your hearts and keep (your) footsteps thereby firm. (Qur'an, 8:11)
In this background, look at the insinuation of some Western "scholars" who have written that the Holy Prophet (s.a.w.a.) had taken control of the stream of Badr and by refusing water to Meccans, reduced them to defeat! Anyhow, the facts of the actual battle are, in short, as follows:
With an ill-equipped body of three hundred and thirteen persons, having among them only two horses and seventy camels, the Prophet proceeded to Badr, about eighty miles from Medina, to meet the Meccan army. The forces met on the 17th of the month of Ramadhan, 2 A.H. (624 A.D.). After individual combats according to the custom of the Arabs, between Hamza, 'Ali and Ubaidah (all Hashimites) on the side of the Muslims and Utbah, Shaibah and Walid ibn 'Utbah (all Umayyads) from the Meccan ranks, a pitched battle ensued.
The stakes were high. Both forces fought valiantly but the Muslims were animated by holy zeal. In the thick of the battle, the Prophet prayed to God, earnestly beseeching Him thus: "O Lord, forget not Thy promise of assistance! O Lord! If this little band were to perish, there will be none to offer worship unto Thee."
Allah describes it in the following verses:
(Recall) when you sought aid from your Lord, so He answered you: I will assist you with a thousand angels following one another. And Allah only gave it as a good news and so that your hearts might thereby be at ease, and victory is only from Allah; surely Allah is Mighty, Wise. (Qur'an, 8:9-10)
The Muslims got the upper hand. The Meccans were driven back, leaving seventy dead, including a number of their notable chiefs. Out of 70, thirty-five were killed by 'Ali ibn Abi Talib alone. It was his first war. Seventy others were taken prisoners. The Muslim force had lost fourteen men.
The prisoners were treated with exceptional kindness. Even the hostile critic Muir says:
"In pursuance of Mahomet's commands, the citizens of Medina and such of the refugees as possessed houses received the prisoners and treated them with much consideration. 'Blessings be on the men of Medina', said one of these prisoners in later days, 'they made us ride while they themselves walked; they gave us wheaten bread to eat when there was little of it, contenting themselves with dates'."
The more affluent prisoners paid the ransom and were set free. The others were asked to teach ten persons each to read and write and this teaching was to count as their ransom. After all, in these times of progress and enlightenment, with all the charters and agreements on the treatment of prisoners of war, history does not record another instance even remotely as generous and as humane as the Muslims' treatment of the prisoners taken in their very first encounter fourteen hundred years ago. Source: Al-islam.org