Musnad Ahmad 1067:1

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from al-Zuhri, Mahmud ibn Labid narrated to me: That he remembered the Messenger of Allah, may Allah bless him and grant him peace, and he remembered a mouthful of water that the Prophet, may Allah bless him and grant him peace, spat out from a bucket that was in their house.