Musnad Ahmad 1007:64

He said: I read to Abd al-Rahman: Malik, and Ishaq—meaning Ibn Isa—narrated to us, Malik informed me, from Ishaq ibn Abdullah ibn Abi Talhah, from Humaydah bint Ubayd ibn Rifa'ah, from Kabshah bint Ka'b ibn Malik—Ishaq said in his hadith: And she was under the wife of Ibn Abi Qatadah—that Abu Qatadah entered upon her, and she poured water for his ablution. A cat came to drink from it, so he tilted the vessel for it until it drank. Kabshah said: He saw me looking at him, so he said: "Are you surprised, O daughter of my brother?" She said: "Yes." He said: "Indeed, the Messenger of Allah (peace and blessings of Allah be upon him) said: 'It is not impure; it is among those who go around among you, the males and the females.'" And Ishaq said: Or "the females."