Musnad Abu Ya'la al-Mawsili 209:139

Abu Khaythama narrated to us, Mu'awiyah ibn 'Amr narrated to us, Za'idah narrated to us, from 'Abd al-Malik ibn 'Umayr, from Rib'i ibn Hirash, from Umm Salamah, who said: The Messenger of Allah (may Allah bless him and grant him peace) entered upon me while his face was sorrowful. She said: I reckoned that was due to an ailment. I said: "O Messenger of Allah, what is the matter with you, your face is sorrowful?" He said: "Because of the seven dinars that we hid yesterday; we reached the evening and did not distribute them, and they are in the corner of the mattress."