مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2635
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
Abu Jamrah told us; I heard Ibn 'Abbas (رضي الله عنه) say: I was a boy playing with other boys; I turned around and saw the Prophet of Allah (ﷺ) coming towards me. I said: The Prophet of Allah (ﷺ) is only coming to me, so I ran and hid behind a door. But suddenly he grabbed me by the back of the neck and gave me a slap between the shoulders and said: "Go and call Mu'awiyah for me” - as he was his scribe. So I ran and said: Go to the Messenger of Allah (ﷺ); he wants to talk to you.
Musnad Ahmad 2651lts isnad is hasan]