The Book of Fasting
حَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ، قَالَ حَدَّثَنَا مُعْتَمِرُ بْنُ سُلَيْمَانَ، عَنْ إِسْحَاقَ بْنِ سُوَيْدٍ، وَخَالِدٍ عَنْ عَبْدِ الرَّحْمَنِ بْنِ أَبِي بَكْرَةَ، عَنْ أَبِي بَكْرَةَ، أَنَّ نَبِيَّ اللَّهِ صلى الله عليه وسلم قَالَ " شَهْرَا عِيدٍ لاَ يَنْقُصَانِ " . فِي حَدِيثِ خَالِدٍ " شَهْرَا عِيدٍ رَمَضَانُ وَذُو الْحِجَّةِ " .Abd ar-Rahman b. Abu Bakra reported on the authority of Abu Bakra that the Messenger of Allah (ﷺ) had said:The months of 'Id are not incomplete. And in the hadith narrated by Khalid (the words are):" The months, of 'Id are Ramadan and Dhu'l-Hijja
From Sahih Muslim, whose reports the scholars accept as authentic.