Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) said that on the day of Badr the Prophet (peace and blessings be upon him) said: "Whoever does such-and-such and reaches such-and-such a place, he shall have such-and-such." So the young men rushed forward to it, while the elders stayed by the banners. When victory was granted to them, the young men came demanding what had been set for them, and the elders said: Do not take it all without us, for we were your support behind you. So Allah Almighty revealed this verse: "They ask you about the spoils of war. Say: The spoils of war belong to Allah and the Messenger, so fear Allah and set things right between yourselves." [Surah al-Anfal: 1]
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الفيء والغنيمة / 12817