Musnad Ahmad 421:1

Abdullah ibn Ahmad said: Nasr ibn Ali narrated to me, he said: Yusuf ibn Khalid narrated to us, he said: Abu Ja’far al-Khatmi narrated to us, from Abd al-Rahman ibn Uqbah ibn al-Fakih, from his grandfather, al-Fakih ibn Sa’d—and he had companionship [with the Prophet]—that the Messenger of Allah, peace and blessings of Allah be upon him, "used to perform ghusl on the day of Jumu’ah, the day of Arafah, the day of al-Fitr, and the day of al-Nahr." He said: "And al-Fakih ibn Sa’d used to command his family to perform ghusl on these days."