Sahih Muslim
The Book of Prayers (Kitab Al-Salat)
Book Number: 004 / Hadith Number: 891
Ibn Umar reported: The Messenger of Allah (may peace be upon him) said: Do not deprive women of their share of the mosques, when they seek permission from you. Bilal said: By Allah, we would certainly prevent them. 'Abdullah said: I say that the Messenger of Allah (may peace be upon him) said it and you say: We would certainly prevent them!