It is narrated from Hazrat Anas (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: Whoever performs forty prayers in my mosque in such a way that not a single prayer is missed, for him is written freedom from Hell, salvation from punishment, and exemption from hypocrisy.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 12583
Hadith Gradingحکم دارالسلام:إسناده ضعيف لجهالة نبيط بن عمر