Musnad Ahmad 25:408

Surayj ibn al-Nu‘man narrated to us, Hushaym narrated to us, Husayn informed us, from ‘Ikrimah, from Ibn ‘Abbas, who said: "I have memorized the entire Sunnah, except that I do not know whether the Messenger of Allah, may Allah bless him and grant him peace, used to recite [aloud] in the Dhuhr and ‘Asr prayers or not. And I do not know how he used to recite this letter: 'wa qad balaghtu min al-kibari ‘itiyya' (and I have reached extreme old age) or '‘asiyya'?"