Musnad Ahmad 1007:121

Mu'ammar ibn Sulayman al-Raqqi narrated to us, Hajjaj narrated to us, from Qatadah, from 'Abdullah ibn Abi Qatadah, from his father, that: Water for ablution was placed for him, and a cat lapped from it. He began to perform ablution with it. They said, "O Abu Qatadah, the cat has lapped from it!" He said, "I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: 'The cat is of the household, and it is among those who roam around among you.'"