Musnad Ahmad 1159:16

Yahya ibn Ghaylan narrated to us, he said: Al-Mufaddal, meaning Ibn Fadalah, narrated to us, from Khalid ibn Yazid, from ‘Ata’, that he said: ‘Anbasah ibn Abi Sufyan narrated to us, he said: I heard Umm Habibah, the Mother of the Believers, saying: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "Whoever prays twelve rak'ahs in his night and his day, other than the obligatory ones, Allah will build for him a house in Paradise."