Musannaf Ibn Abi Shayba 3:1760

Hushaym narrated to us, from Sa'id ibn al-Marzuban, from Abu Wa'il, from 'Abdullah, that he used to conceal "Bismillahi-r-Rahmani-r-Rahim" (In the name of Allah, the Most Gracious, the Most Merciful), the seeking of refuge (al-isti'adhah), and "Rabbana wa laka al-hamd" (Our Lord, and to You is the praise).