It is narrated from Sayyiduna Hanzalah al-Usayyidi (may Allah be pleased with him), who used to be called the scribe of the Messenger of Allah (peace and blessings be upon him), that the Messenger of Allah (peace and blessings be upon him) said: "Whoever guards the five prayers, or the obligatory prayer, with its ablution, its times, its bowing and its prostration, and regards it as a duty upon himself, Allah makes the Fire forbidden for him."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 3481