Musnad Abu Ya'la al-Mawsili 151:58

Mus'ab ibn 'Abd Allah al-Zubayri narrated to us, Ibrahim ibn Sa'd narrated to us, from Salih ibn Kaysan, from Ibn Shihab, from 'Ubayd Allah ibn 'Abd Allah, that Ibn Mas'ud said: While we were with the Messenger of Allah (may Allah bless him and grant him peace), numbering close to thirty men, none among them but a Qurayshi—by Allah, I have never seen the faces of men more beautiful than their faces were that day—he said: They mentioned women and spoke about them, and he spoke with them until I wished he would be silent. Then he came to us, testified [to the oneness of Allah], and then said: "As for what follows, O assembly of Quraysh, you are the people of this affair as long as you obey Allah. But when you disobey Him, He will send upon you those who will strip you as this rod is stripped," referring to a rod in his hand. Then he stripped his rod, and it became white and smooth.