Musnad Ahmad 642:3

Ibn Fudayl narrated to us, Husayn narrated to us, from ‘Umarah ibn Ruwaybah, that he saw Bishr ibn Marwan on the pulpit raising his hands, gesturing with his two fingers while supplicating. He said: "May Allah curse these two hands. I saw the Messenger of Allah, may Allah bless him and grant him peace, on the pulpit supplicating, and he was gesturing with one finger."