The Family Of Imran - 3:64
"Say, "People of the Book! Come to a principle which is the same between us and you: "Let us serve none but Allah and associate with Him nothing in common, and let not one of us take the other as gods after Allah."If they refuse, say, "Bear witness, we are Muslims!"
Why does Allah not forgive those who die associating partners?
The Women/4:48
Allah does not forgive associating partners with Him, but other than that He forgives to whom He wills. Whoever associates partners with Allah has committed a great insult.
The Women/4:116
Allah does not forgive associating partners with Him (if it continues until death), but He forgives the sins below that to whom He wills. Whoever associates partners with Allah has gone astray.
Luqman/31:13
"When Lokman advised his son, he said: "My dear son, do not associate partners with Allah; surely shirk (associating partners with God) is a great wrong."
The Companies/39:65
It has been revealed to you and those before you that if you associate partners, all that you do will be in vain and you will be of the losers.