Musnad Ahmad 280:1

Muhammad ibn Ja‘far narrated to us, he said: Shu‘bah narrated to us, from Sulayman, from Abu Wa’il, from ‘Amr ibn al-Harith, from Zaynab, the wife of ‘Abdullah, that she said: The Messenger of Allah (peace and blessings of Allah be upon him) said to the women: "Give charity, even if it is from your jewelry." She said: ‘Abdullah was a man of limited means, so she said to him: "Does it suffice me to place my charity upon you and upon my brother’s children—or children of a brother of mine—who are orphans?" ‘Abdullah said: "Ask the Prophet (peace and blessings of Allah be upon him) about that." She said: So I went to the Prophet (peace and blessings of Allah be upon him), and there was at his door a woman from the Ansar who was also named Zaynab, asking about what I was asking about. Bilal came out to us, and we said: "Go to the Messenger of Allah (peace and blessings of Allah be upon him) and ask him about that, and do not tell him who we are." So he went to the Messenger of Allah (peace and blessings of Allah be upon him), and he said: "Who are they?" He said: "Zaynab." He said: "Which of the Zaynabs?" He said: "Zaynab, the wife of ‘Abdullah, and Zaynab the Ansari woman." He said: "Yes, they have two rewards: the reward of kinship and the reward of charity."