Sahih Muslim Book 31, Hadith Number 6017.

Chapter : The merits of ‘Abdullah b. Mas’ud and that of his mother (Allah be pleased with them).

Abu Musa reported: When I and my brother came from Yemen we used to consider Ibn Mas’ud and his mother amongst the members of the household of Allah’s Messenger (may peace be upon him) because of their visiting them frequently and staying there for long (periods of) time.