Musnad Abu Ya'la al-Mawsili 9:7

Abu Khaythama narrated to us, Yazid bin Harun narrated to us, Isma'il bin Abi Khalid narrated to us, he said: I heard Abu Juhayfah say: I saw the Messenger of Allah, may Allah bless him and grant him peace. The person most resembling him was Al-Hasan bin Ali.