And (remember) when Allah promised you (Muslims) one of the two parties (of the enemy i.e. either the army or the caravan) that it should be yours, you wished that the one not armed (the caravan) should be yours, but Allah willed to justify the truth by His Words and to cut off the roots of the disbelievers (i.e. in the battle of badr).

And know that whatever of war-booty that you may gain, verily one-fifth (1/5th) of it is assigned to Allah, and to the Messenger, and to the near relatives [of the Messenger (Muhammad ﷺ)], (and also) the orphans, Al-Masakin (the poor) and the wayfarer, if you have believed in Allah and in that which We sent down to Our slave (Muhammad ﷺ) on the Day of criterion (between right and wrong), the Day when the two forces met (the battle of badr) - And Allah is Able to do all things.

appear And (remember) when you met (the army of the disbelievers on the Day of the battle of badr), He showed them to you as few in your eyes and He made you as few in their eyes, so that Allah might accomplish a matter already ordained (in His Knowledge), and to Allah return all matters (for decision).

And (remember) when Shaitan (Satan) made their (evil) deeds seem fair to them and said, "No one of mankind can overcome you this Day (of the battle of badr) and verily, I am your neighbour (for each and every help)." But when the two forces came in sight of each other, he ran away and said "Verily, I have nothing to do with you. Verily! I see what you see not. Verily! I fear Allah for Allah is Severe in punishment."

There has already been a sign for you (O Jews) in the two armies that met (in combat i.e. the battle of badr): One was fighting in the Cause of Allah, and as for the other (they) were disbelievers. They (the believers) saw them (the disbelievers) with their own eyes twice their number (although they were thrice their number). And Allah supports with His Victory whom He pleases. Verily, in this is a lesson for those who understand. (See Verse 8:44). (Tafsir At-Tabari)