From Sahih Bukhari (Hadith 6705):
Narrated `Abdullah bin `Umar:that he was asked about a man who had vowed that he would fast all the days of his life then the day of `Id al Adha or `Id-al-Fitr came. `Abdullah bin `Umar said: You have indeed a good example in Allah's Messenger (ﷺ). He did not fast on the day of `Id al Adha or the day of `Id-al-Fitr, and we do not intend fasting on these two days
Reference: Bukhari 6705