It is narrated from Sayyidah Umm Salamah (may Allah be pleased with her) that she said to the Messenger of Allah (peace and blessings be upon him): "Will I receive a reward for spending on the children of Abu Salamah, when I spend on them while they do not share in my own offspring?" He (peace and blessings be upon him) said: "Yes, you will receive a reward for what you spend on them."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20099