Musnad Ahmad 3143

It was narrated from Ibn ‘Abbas (رضي الله عنه) that He was riding a donkey with a boy from Banu Hashim. He passed in front of the Prophet (ﷺ) when he was praying, and he did not stop (his prayer). And two young girls of Banu 'Abdul-Muttalib came and took hold of the Prophet’s knees; he separated them but he did not stop (his prayer).