Yahya related to me from Malik from Yazid ibn Abdullah ibn al-Hadi from Abu Murra, the mawla of Umm Hani, the sister of Aqil ibn AbiTalib, that Abdullah ibn Amr ibn al-As told him that he had visitedhis father Amr ibn al-As and found him eating. His father had invitedhim to eat, and when he replied that he was fasting, his father said,"These are the days on which the Messenger of Allah, may Allah blesshim and grant him peace, forbade us to fast, and told us to break thefast on them."Malik said, "These days are the days oftashriq."
USC-MSA web (English) reference: Book 20, Hadith 138
Arabic reference: Book 20, Hadith 841