Musnad Ahmad 1034:61

Sulayman al-Hashimi narrated to us, Isma'il—meaning Ibn Ja'far—informed us, 'Amr—meaning Ibn Abi 'Amr—informed me, from 'Abdullah ibn 'Abd al-Rahman al-Ash-hali, from Hudhayfah ibn al-Yaman, that the Prophet, peace and blessings of Allah be upon him, said: "By the One in whose hand is my soul, you shall certainly enjoin the good and you shall certainly forbid the evil, or else Allah will soon send upon you a punishment from Him, then you will call upon Him, and He will not answer you."