Sunan Ibn Majah, Book 5, Hadith 1338 (In-Book) ⓘ
Kathir bin ‘Abdullah bin ‘Amr bin ‘Awf narrated, from his father, from his grandfather, that the Messenger of Allah said the Takbir in the ‘Eid prayers, seven times in the first Rak’ah and five times in the second.
حَدَّثَنَا أَبُو مَسْعُودٍ، مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ عُبَيْدِ بْنِ عَقِيلٍ حَدَّثَنَا مُحَمَّدُ بْنُ خَالِدِ بْنِ عَثْمَةَ، حَدَّثَنَا كَثِيرُ بْنُ عَبْدِ اللَّهِ بْنِ عَمْرِو بْنِ عَوْفٍ، عَنْ أَبِيهِ، عَنْ جَدِّهِ، أَنَّ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ كَبَّرَ فِي الْعِيدَيْنِ سَبْعًا فِي الأُولَى وَخَمْسًا فِي الآخِرَةِ .
also referenced under: Hadith 1279 (Reference) & Volume 2, Book 5, Hadith 1279 (DarusSalam)