Musnad Ahmad 1156:200

Husayn ibn Ali narrated to us, from Za'idah, from Abd al-Malik ibn Umayr, who said: Rib'i ibn Hirash narrated to me, from Umm Salamah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) entered upon me, and he was pale-faced. She said: I attributed that to an illness, so I said: "O Messenger of Allah, I see you pale-faced; is it from an illness?" He said: "No, but the seven dinars that were brought to us yesterday, we reached the evening and we had not spent them; I forgot them in the corner of the mattress."