It was narrated from Ibrahim bin Nashit that:
He asked Ibn Shihab about ghusl on Friday. He said: "It is a sunnah; Salim bin 'Abdullah told me, narrating from his father, that the Messenger of Allah (ﷺ) spoke about it from the minbar."
App reference: Book 14, Hadith 43
English reference: Vol. 2, Book 14, Hadith 1407
Arabic reference: Book 14, Hadith 1417