مُسْنَدُ أَحْمَدَ
Musnad Ahmad 3193
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated from Ibn 'Abbas (رضي الله عنه) that The Prophet (ﷺ) carried him and his brother (on his mount), one in front of him and one behind.
Musnad Ahmad 3217lts isnad is da'eef because Jabir al-Jufi is da'eef]