Musnad Ahmad 31:667

Abu al-Ala al-Hasan ibn Siwar narrated to us, he said: Layth narrated to us, from Khalid—meaning Ibn Yazid—from Sa’id, from Abu Bakr ibn al-Munkadir, that ‘Amr ibn Sulaym informed him, from ‘Abd al-Rahman ibn Abi Sa’id, from his father, from the Messenger of Allah (may Allah bless him and grant him peace) that he said: "Indeed, the ritual bath (ghusl) on the day of Friday is [incumbent] upon every person who has reached puberty, and the use of the tooth stick (siwak), and that he applies of perfume whatever he is able to."