Musnad Ahmad 28:100

Abu Abd al-Rahman narrated to us, Sa'id narrated to us, Ka'b ibn Alqamah narrated to me, from Isa ibn Hilal al-Sadafi, from Abdullah ibn Amr, from the Prophet, peace and blessings of Allah be upon him, that he mentioned the prayer one day and said: "Whoever maintains it, it will be for him a light, a proof, and a salvation on the Day of Resurrection. And whoever does not maintain it, there will be no light for him, nor proof, nor salvation, and he will be on the Day of Resurrection with Qarun, Pharaoh, Haman, and Ubayy ibn Khalaf."