The Description of the Prophet, may Allah Bless Him and Grant Him Peace
Malik :: Book 49 : Hadith 49.7.12
Yahya related to me from Malik from Ayyub ibn Habib, the mawla of Sad ibn Abi Waqqas that Abu'l-Muthanna al-Juhani said, "I was with Marwan ibn al-Hakam and Abu Said al-Khudri came to him. Marwan ibn al-Hakam said to him, 'Have you heard that the Messenger of Allah, may Allah bless him and grant him peace, forbade blowing into drinks?' Abu Said said to him, 'Yes.' A man said to him, 'Messenger of Allah, I am not quenched from one breath.' The Messenger of Allah, may Allah bless him and grant him peace, said to him, 'Remove the cup from your mouth and then breathe.' He said, 'Sometimes I see something floating in it?' He said, 'Then pour it out.'"