كتاب الصوم
7  
Fasting
(4a)
Chapter: Keeping the Fast free from Imperfection - Section 1
(3)
باب تنزيه الصوم - الفصل الأول
Mishkat al-Masabih 2002
Ibn ‘Abbas said that the Prophet had himself cupped when he was wearing the ihram and also when he was fasting. (Bukhari and Muslim.)
وَعَنِ ابْنِ عَبَّاسٍ قَالَ: إِنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ احْتَجَمَ وَهُوَ مُحْرِمٌ وَاحْتَجَمَ وَهُوَ صَائِمٌ
  مُتَّفَقٌ عَلَيْهِ   (الألباني) حكم   :
Reference : Mishkat al-Masabih 2002
In-book reference : Book 7, Hadith 46