Musnad Ahmad 27:603

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from Tawbah al-'Anbari, who said: I heard Murriq al-'Ijli, who said: I heard a man ask Ibn 'Umar—or he asked Ibn 'Umar—and he said: "Do you pray the Duha (forenoon) prayer?" He said: "No." He said: "Did 'Umar?" He said: "No." He said: "Abu Bakr?" He said: "No." He said: "Then the Messenger of Allah, may Allah bless him and grant him peace?" He said: "I do not think so."