I heard the Messenger of Allah ﷺ say, "Whoever declares that there is no god but Allah and rejects whatever is worshipped besides Allah, his wealth and his blood become inviolable, and his reckoning rests with Allah."
سمعت رسول الله ﷺ يقول: من قال لا إله إلا الله، وكفر بما يعبد من دون الله، حرم ماله ودمه وحسابه على الله.
Muslim narrated it in the Book of Faith (23), from Suwayd bin Saeed and Ibn Abu Umar, who both said, "Marwan Fazari narrated to us, from Abu Malik," and he related it. Abu Malik's name was Saad bin Tariq bin Ashim Ashjai.