The unseen help of Allah ﷻ (exalted is His majesty) (Badr), added by this site

Allah’s ﷻ (exalted is His majesty) assistance came to the Muslims in the form of rain. As a result, the sandy ground became firm and the entire army had drinking water for themselves and their animals. All of them filled their containers and had even built a pond to store the rain water. Due to the rain, the area that the disbelievers took control of became muddy and this made walking there difficult.