Hadith 504340
Chapter 10: The Two 'Ids - كتاب العيدين
وَحَدَّثَنِي عَنْ مَالِكٍ، أَنَّهُ بَلَغَهُ أَنَّ أَبَا بَكْرٍ، وَعُمَرَ، كَانَا يَفْعَلاَنِ ذَلِكَ .
Yahya related to me from Malik that he had heard that Abu Bakr and Umar used to do that.
Reference Muwatta Malik 504340
USC-MSA web (English) reference : Book 10, Hadith 4