Musnad Ahmad 33:1044

Abu Sa’id narrated to us, Za’idah narrated to us, ‘Abdullah ibn Muhammad ibn ‘Aqil narrated to us, from Jabir ibn ‘Abdullah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The best of the men’s rows is the first, and the worst of them is the last. And the best of the women’s rows is the last, and the worst of them is the first. O assembly of women, when the men prostrate, lower your gazes, so that you do not see the ‘awrahs (private parts) of the men due to the tightness of the lower garments."