Musnad Abu Ya'la al-Mawsili 155:337

Al-Harith ibn Surayj narrated to us, Marwan narrated to us, from Yazid ibn Kaysan, from Abu Hazim, from Abu Hurayrah, who said: A man from the Ansar took a blade while the Prophet, may Allah bless him and grant him peace, was in the house of the Ansari. The Prophet, may Allah bless him and grant him peace, said: "Beware of the milch animal."