كتاب صفة النبى صلى الله عليه وسلم
49  
The Description of the Prophet, may Allah Bless Him and Grant Him Peace

Yahya said that Malik was asked, "Can a woman eat with other than her relative or slave?" Malik said, "There is no harm in that if it is in a manner which is accepted for a woman to eat with men."

Malik said, "A woman sometimes eats with her husband and with others he dines with or with her brother in the same way. It is disapproved of for a woman to be alone with a man when there is no relationship between them by blood, marriage or suckling that would prevent him marrying her."

USC-MSA web (English) reference : Book 49, Hadith 35