Musnad Ahmad 1233:6

Isma'il ibn Muhammad narrated to us, he said: Marwan ibn Mu'awiyah narrated to us, he said: Abu Malik al-Ashja'i narrated to us, he said: My father narrated to me, he said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "Whoever professes the oneness of Allah and disbelieves in what is worshipped besides Him, his wealth and his blood become inviolable, and his reckoning is with Allah, the Almighty and Majestic."