It was narrated from Ibn 'Abbas that Maimunah the wife of the Prophet (ﷺ) said:"Whoever prays in the Masjid of the Messenger of Allah (ﷺ) (that is good), for I heard the Messenger of Allah (ﷺ) say: ' One prayer offered there is better than a thousand prayers offered elsewhere, except the Masjid of the Ka'bah.'"
أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا اللَّيْثُ، عَنْ نَافِعٍ، عَنْ إِبْرَاهِيمَ بْنِ عَبْدِ اللَّهِ بْنِ مَعْبَدِ بْنِ عَبَّاسٍ، أَنَّ مَيْمُونَةَ، زَوْجَ النَّبِيِّ صلى الله عليه وسلم قَالَتْ مَنْ صَلَّى فِي مَسْجِدِ رَسُولِ اللَّهِ صلى الله عليه وسلم فَإِنِّي سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " الصَّلاَةُ فِيهِ أَفْضَلُ مِنْ أَلْفِ صَلاَةٍ فِيمَا سِوَاهُ إِلاَّ مَسْجِدَ الْكَعْبَةِ " .
Nesai
The Book of the Masjids • Hadith 691