It is reported from Sa'id bin Jubayr (may Allah have mercy on him), concerning this saying of Allah Almighty: "The sadaqat are only for the poor" [Surah al-Tawbah: 60], that he said to a man: If you give the sadaqah to one category, it will suffice you.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قسم الصدقات / 13133