Hadith 29:167
A sheikh of ours narrated to us, he said: I heard Ja’far, from his father, who said: Ali accepted Islam while he was seven years old. The Messenger of Allah, may Allah bless him and grant him peace, was taken (in death) while he (Ali) was twenty-seven years old. And Umar was killed while he (Ali) was fifty-seven years old.
حدثنا شيخ لنا قال سمعت جعفرا عن أبيه قال أسلم علي وهو بن سبع وقبض رسول الله صلى الله عليه وسلم وهو بن سبع وعشرين وقتل عمر وهو بن سبع وخمسين