Sayyiduna Ibn Mas'ud (may Allah be pleased with him) says that I have fasted thirty days of Ramadan with the Prophet (peace and blessings of Allah be upon him) more frequently than I have fasted twenty-nine (29) days.
Hadith Referenceمسند احمد / مسند المكثرين من الصحابة / 3776
Hadith Gradingحکم دارالسلام:حسن لغيره، وهذا إسناد ضعيف لجهالة حال دينار والد عيسي.