Musnad Ahmad 2:202

Isma'il ibn Ibrahim narrated to us, from Yahya ibn Abi Ishaq, from Salim ibn 'Abdullah, who said: 'Umar was a jealous man. When he would go out to prayer, 'Atikah bint Zayd would follow him. He disliked her going out, and he disliked forbidding her. He used to narrate that the Messenger of Allah, peace and blessings of Allah be upon him, said: "If your women ask your permission to go to prayer, do not forbid them."