I was with Muawiya when he said, "The Messenger of Allah ﷺ died at the age of sixty-three, Abu Bakr died at the age of sixty-three, and Umar
died at the age of sixty-three."
حدثنا أبو نعيم حدثنا يونس عن أبي السفر عن عامر
كنت عند معاوية فقال توفي رسول الله ﷺ وهو ابن ثلاث وستين وتوفي أبو بكر رضي الله عنه وهو ابن ثلاث وستين وتوفي عمر رضي الله عنه وهو ابن ثلاث وستين
Its isnad is sahih. It is a lofty chain despite the number of its narrators, for Abu Safr, who is Saeed bin Muhammad, narrates from someone of his own generation, namely Amir bin Saad bin Abu Waqqas. As for Jareer, he is Ibn Abdullah al-Bajali, the companion. The hadith has already appeared at 16816.