What did Allah's Messenger (peace be upon him) say about a Muslim servant (of Allah) who prays for the sake of Allah twelve rak'ahs (of Sun'an) each day on top of the obligatory ones?
 Umm Habiba, the wife of the Apostle of Allah (may peace be upon him), reported Allah's Messenger (may peace be upon him) as saying:                      If any Muslim servant (of Allah) prays for the sake of Allah twelve rak'ahs (of Sun'an) every day, over and above the obligatory ones, Allah will build for him a house in Paradise, or a house will be built for him in Paradise; and I have not abandoned to observe the in after (hearing it from the Messenger of Allah). (So said also 'Amr and Nu'man.)