بلوغ المرام
Bulughul Maram
Hadith Number: 933
وعن ابن عباس رضي الله عنهما قال: كان إيلاء الجاهلية السنة والسنتين فوقت الله اربعة اشهر فإن كان اقل من اربعة اشهر فليس بإيلاء. اخرجه البيهقي.
Narrated Ibn 'Abbas (RA): The swearing to stay away from one's wife in al-Jahiliyyah era was for one or two years. Then, Allah appointed a period of four months for it. So, if it is less than four months, it is not swearing to stay away from one's wife. [al-Baihaqi reported it]