Musnad Ahmad 25:924

Surayj narrated to us, Nuh ibn Qays narrated to us, from ‘Amr ibn Malik al-Nukri, from Abu al-Jawza’, from Ibn ‘Abbas, who said: "There was a beautiful woman who used to pray behind the Messenger of Allah, peace and blessings of Allah be upon him. Some of the people would move forward to the first row so as not to see her, and some of them would move backward until they were in the last row. When he would bow, he would look from under his armpits. So Allah revealed regarding her affair: 'And We have already known the preceding [ones] among you, and We have already known the succeeding [ones].' [Al-Hijr: 24]"