Musnad Ahmad 25:612

Husayn and Ahmad ibn Abd al-Malik narrated to us, they said: Ubayd Allah—meaning Ibn Amr—narrated to us, from Abd al-Karim, from Ibn Jubayr. Ahmad said: From Sa’id ibn Jubayr, from Ibn Abbas, from the Prophet, peace and blessings of Allah be upon him, who said: "There will be a people at the end of time who will dye [their hair] with this black color—Husayn said: like the crops of pigeons—they will not smell the fragrance of Paradise."