Al-Hasan (may Allah have mercy on him) said concerning this saying: "And they give food, out of love for Allah, to the poor, the orphans and the captives" [Surah al-Insan: 8], meaning (the captives) from the polytheists.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب السير / 18333