Habib bin Maslamah (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) "gave a quarter of the spoils at the beginning (of the expedition) and a third on the return."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الفيء والغنيمة / 12801