Muhammad bin Ishaq narrates with his chain; at its end it says that he (peace and blessings be upon him) said: "Go to the one who collects the charity from Banu Zurayq; he will give you a wasq of dates. Feed sixty poor people, and feed the rest to yourself and your family." This indicates that sixty poor people were given from the wasq, and he himself ate from what remained.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الظهار / 15282