Musnad Abu Ya'la al-Mawsili 209:67

Abu al-Husayn al-Razi narrated to us, Muhammad ibn 'Aziz narrated to us, he said: Salamah informed me, from 'Uqayl, from Ibn Shihab, from Salim ibn 'Abd Allah, that he informed him that Safinah, the freed slave of Umm Salamah, the wife of the Prophet (may Allah bless him and grant him peace), informed him that Umm Salamah, the wife of the Prophet (may Allah bless him and grant him peace), said: The Messenger of Allah (may Allah bless him and grant him peace) said: "The angels do not accompany a traveling party in which there is a bell."