I heard the Messenger of Allah ﷺ say, "A prayer in this mosque of mine is better than a thousand prayers in any other mosque, except for the Mosque of the Kaabah."
حدثنا عبد الرزاق قال أخبرنا ابن جريج قال سمعت نافعا مولى ابن عمر يقول حدثنا إبراهيم بن عبد الله بن معبد أن ابن عباس حدث أن
سمعت رسول الله ﷺ يقول صلاة في مسجدي هذا أفضل من ألف صلاة فيما سواه إلا مسجد الكعبة
Its isnad is sahih. Ibrahim bin Abdullah bin Mabad is the son of Abbas bin Abdul-Muttalib. He narrates from Ibn Abbas, his grandfather's brother, and he is trustworthy. His hadith appears in Muslim, and the hadith has already been given at 26715.