It is narrated from Hazrat Umm Habibah that the Prophet (peace and blessings be upon him) said: Whoever among the Muslims performs ablution well and, in addition to the obligatory prayers, offers four (voluntary) rak'ahs in the way of Allah in a day, Allah will build a house for him in Paradise. Then each narrator of this hadith clarified regarding himself that he always performed these rak'ahs.