Musnad Ahmad 1163:40

'Abd al-Razzaq narrated to us, he said: Ibn Jurayj informed us, he said: I heard Nafi', the freed slave of Ibn 'Umar, saying: Ibrahim ibn 'Abd Allah ibn Ma'bad narrated to us, that Ibn 'Abbas narrated that Maymunah, the wife of the Prophet, may Allah bless him and grant him peace, said: I heard the Messenger of Allah, may Allah bless him and grant him peace, saying: "A prayer in this mosque of mine is better than a thousand prayers in what is other than it, except for the Mosque of the Ka'bah."