It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that when the Messenger of Allah (peace and blessings be upon him) was setting out for Badr, he said: "Allah, the Mighty and Majestic, has promised me Badr (victory at it), and that He will give me their army as spoils. Whoever kills a man shall have such-and-such of their spoils, if Allah wills; and whoever captures a man shall have such-and-such of their spoils, if Allah wills." When the two armies faced each other, Allah cast terror into the hearts of the polytheists; then, when they fought, Allah defeated them. The swiftest of the people pursued them, killed seventy and captured seventy.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12621