Silsilat al-Ahadith al-Sahihah

Sayyidah Umm Abdullah (may Allah be pleased with her), who was the sister of Sayyiduna Shaddad bin Aws (may Allah be pleased with him), sent a bowl of milk to the Prophet Muhammad (peace and blessings be upon him) at the time of iftar due to the long day and intense heat. However, the Messenger of Allah (peace and blessings be upon him) returned the messenger and said, "(Go and ask) where was this milk obtained from?" She replied that it was the milk of her own goat. The Messenger of Allah (peace and blessings be upon him) again sent the messenger back, saying, "(Go and ask) where was that goat obtained from?" She said, "I bought it in exchange for my own wealth." Then, after such thorough inquiry, the Prophet (peace and blessings be upon him) drank it. The next day, Umm Abdullah (may Allah be pleased with her) herself came to the Messenger of Allah (peace and blessings be upon him) and said, "O Messenger of Allah! Because of the long day and intense heat, I felt compassion for you and sent a bowl of milk (yesterday), but you returned my messenger to me to investigate (why is that)?" The Messenger of Allah (peace and blessings be upon him) said, "The messengers before me were commanded to eat only tayyib (i.e., lawful) things and to do only righteous deeds."