Sahih Muslim | Book 9 | Hadith Number 3492

Narrated by Abu Sahba'
Abu Sahba' said to Ibn 'Abbas (Allah be pleased with them): Do you know that three (divorces) were treated as one during the lifetime of Allah's Apostle (may peace be upon him), and that of Abu Bakr, and during three (years) of the caliphate of Umar (Allah be pleased with him)? Ibn Abbas (Allah be pleased with them) said: Yes.