Surah 'Ali-Imran...
"Indeed there has been a sign for you in the two hosts that encountered: one fighting in the path of Allah and the other disbelieving; they (infidels) saw twice as many as they were with the sight of the eye; and Allah confirms with His aid whom He pleases. Surely there is a lesson herein for those who have insight." This fact has been recorded in books, including: Majma'-ul-Bayan, Maraqi, Fakhr Razi and many other ones that this verse concerns Battle of Badr.
In that fighting, Muslims struggled against infidels. The number of Muslims was 313 men, among whom 77 figures were from the Emigrants and 236 men from the Helpers ( Ansar ) for whom Sa'd-ibn-'lbadah was the flagman. As military equipment, Muslims had only seventy camels, two horses, six armours, and eight swords; while the opposite army, the pagans, were one thousand men with one hundred horses.
The Muslims won the battle wherein twenty two of them became martyrs: 14 martyrs from the Emigrants and 8 martyrs from the helpers, when hostile pagans had to give seventy killed persons and 170 men as captives. This incident is a lesson for those who have intellect and sight that how a small group of Muslims with little equipment could defeat an equipped army the number of whose fighters was three-fold of Muslims. This shows that mere material possibilities are not the enough cause of victory.
"Indeed there has been a sign for you in the two hosts that encountered: one fighting in the path of Allah and the other disbelieving; they (infidels) saw twice as many as they were with the sight of the eye..." Explanations The victory in the Battle of Badr, by a few persons against a larger number of equipped fighters, is the prevalence of Allah 's Will over people's will. It is the best example of prevalence of Truth over untruth and Faith over disbelief. "...
and Allah confirms with His aid whom He pleases..." Wherever Allah pleases, visions, recognitions, and thoughts vary: with these very eyes, they see the same crowd twofold.