This hadeeth comes under the following chapter: IT IS OBLIGATORY TO ABSTAIN FROM ADORNMENT DURING THE 'IDDA PERIOD, BUT MOURNING BEYOND THREE DAYS IS PROHIBITED
Safiyya bint Abu 'Ubaid reported on the authority of Hafsa or 'A'isha (Allaah be pleased with thein) or from both of them that Allaah's Messenger (may peace he upon him) said: It is not permissible for a woman believing in Allaah and the Hereafter (or believing in Allaah and His Messenger) that she should observe mourning for the dead beyond three days except in case of her husband.