The Bee - 16:125
Call to the Way of your Lord with wisdom and good enlightenment. Argue with them in the best way. Your Lord knows best those who deviate from His way and those who are on the right path.
The call to Allah is to serve Allah alone, and not to associate any partner with Him:
The Cave/18:110
"Say, "I am nothing but a human being like you. It has been revealed to me that your God is one God. So let everyone who hopes to meet his Lord do righteous deeds and associate no partner in the worship of his Lord."
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!"
Explained in Detail/41:5
"They said: "We are fixed in our minds against what you call us to, and there is a heaviness in our ears and a veil between us and you. Do what you will, and we will do it."
Explained in Detail/41:6
"Say, "I am only a man like you, and it has been revealed to me that your God is one God. Turn to Him and ask forgiveness from Him. Woe to those who associate partners!"
Prophet Hud/11:62
"They said: "O Salih, before this you were a popular source of hope among us. Do you now forbid us from what our forefathers used to serve? We are in doubt about what you call us to."
The Thunder/13:36
"Those to whom We have given the Book rejoice at what has been sent down to you. Some groups disbelieve in part of it. Say: "I am commanded to serve Allah and to associate no partners with Him, to Him I call and to Him is my return."
The Family Of Imran/3:18
Allah testifies that there is no god but Him, and the angels and the learned who observe justice. There is no god but Him. He is the Exalted, the Wise.
The Family Of Imran/3:79
"No man to whom Allah has given the Book, wisdom and prophethood calls the people to Him, saying: "Serve me after Allah". Rather, he says, "Be servants devoted to your Lord in accordance with the Book which you have learned and taught"."