Hadith 8:1667
Abu Bakr narrated to us, he said: Hafs narrated to us, from Hisham, from Ibn Sirin, who said: The companions of the Messenger of Allah (may Allah bless him and grant him peace) performed Hajj separately (Ifrad) for forty years after him, and they were the most strictly following of his Sunnah: Abu Bakr, Umar, and Uthman.
حدثنا أبو بكر قال حدثنا حفص عن هشام عن بن سيرين قال أفرد أصحاب رسول الله صلى الله عليه وسلم الحج بعده أربعين سنة وهم كانوا لسنته أشد أتباعا أبو بكر وعمر وعثمان