Musnad Ahmad 27:1190

Abu Abd al-Rahman narrated to us, Sa’id—meaning Ibn Abi Ayyub—narrated to us, Ka’b ibn Alqamah narrated to me, from Bilal ibn Abdullah ibn Umar ibn al-Khattab, from his father, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Do not prevent the women from their shares of the mosques if they ask your permission." Bilal said: "By Allah, we will certainly prevent them." Abdullah said: "I say: 'The Messenger of Allah (peace and blessings of Allah be upon him) said,' and you say: 'We will certainly prevent them!'"