The sayings of Prophet Muhammad peace be upon him

[أبوسيف]

Umm Habibah (r.a.) the mother of the believers, reported:'I heard the Messenger of Allah (PBUH) saying, A house will be built in Jannah for every believer who offers twelve Rakah of optional prayer other than the obligatory prayer in a day and a night

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Commentary
If one makes it a practice to offer (at least) twelve extra rakahs in addition to the five obligatory prayers, the Messenger of Allah (saws) gave them the glad tiding of a house which would be built for them in Paradise.
The twelve extra (or Nafl) rakahs which the Prophet (saws) never failed to offer, and which are known as Sunnah Muaqqedah are:
Two rakahs before the 'Fajr' prayer.
Four rakahs before the 'Dhuhr' prayer and two rakahs after it.
Two rakahs after the 'Magrib' prayer.
Two rakahs after the 'Isha' prayer.

عن أم حبيبة رضي الله عنها في سنن الترمذي ، قالت سمعت رسول الله صلى الله عليه و سلم يقول: "من صلى في يوم وليلة ثنتي عشرة ركعة بني له بيت في الجنة: أربعاً قبل الظهر، وركعتين بعدها، وركعتين بعد المغرب، وركعتين بعد العشاء، وركعتين قبل صلاة الفجر".