عَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ رَضِيَ اللَّهُ عَنْهُ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ نَهَى عَنْ صَوْمِ يَوْمِ الْفِطْرِ وَيَوْمِ الْأَضْحَى
It is narrated from Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him and his family) forbade fasting on the days of Eid al-Fitr and Eid al-Adha.