The Battle of Badr happened on the 17th of Ramadan, two years after Prophet Muhammad ﷺ moved to Madinah. 14 friends of the Prophet died in the battle.
It was a big deal for Muslims because it was their first major battle. About 313 Muslim soldiers fought against 1000 soldiers from the Quraysh tribe. With Allah's help, the Muslims won.
This battle was super important for Islam. It showed how strong and brave the Muslim community was. It also helped them become more powerful. In the Quran, it's called Yawm al-Furqan (The Day of the Criterion).
When Prophet Muhammad ﷺ asked Allah for help, Allah sent 1000 angels to support them. Badr is about 130 km away from Madinah.
"When you asked for help from your Lord, He answered you. Indeed I will aid with a thousand of the angles in rows behind rows." (Quran 8:9)