The Prophet ﷺ was praying when two young girls from the family of Abdul-Muttalib came and grabbed hold of his knees, so he gently separated them.
حدثنا وكيع حدثنا شعبة عن الحكم عن يحيى بن الجزار عن صهيب
كان النبي ﷺ يصلي فجاءت جاريتان من بني عبد المطلب حتى أخذتا بركبتيه ففرع بينهما
Its isnad is sahih. Yahya bin Jazzar was a trustworthy tabii, he heard from Ali as we mentioned at 1132, and he also narrated from Ibn Abbas, but here he narrated from him through an intermediary, Suhayb, who is Abu Sahba, the freedman of Ibn Abbas. He is trustworthy. Abu Zura confirmed his reliability, and Ibn Hibban mentioned him in al-Thiqat. Tahdhib states that Nasai declared him daif, but I did not find him mentioning this in Kitab al-Duafa.His statement "he separated between the two" means he distinguished between them, as in Abu Dawud 1:261 and Nihayah 3:195. The hadith will come at greater length at 2258. See also 1891.