Musnad Ahmad 675:3

'Abd al-Wahhab ibn 'Abd al-Majid al-Thaqafi narrated to us, from Khalid, from al-Hakam, from 'Abd Allah ibn 'Ukaym, who said: "The Messenger of Allah (peace and blessings of Allah be upon him) wrote to us one month before his death: 'Do not make use of the dead animal's hide, nor its sinew.'"