Umm Salamah (may Allah be pleased with her) says: I said: O Messenger of Allah (peace and blessings be upon him)! The sons of Abu Salamah (may Allah be pleased with him) are in my care, and they have nothing except what I spend on them, and I cannot abandon them in such and such a state. If I spend on them, will I have any reward for it? The Prophet (peace and blessings be upon him) said: "Whatever you spend on them, you will surely be rewarded for it."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الزكاة / 7761