From Sahih Muslim (Hadith 2532):
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
Reference: Muslim 2532