Assalamu 'alaikum - Allah says in the Qur'an

Say (O Muhammad-peace be upon him): "This is my way; I invite unto Allâh (i.e. to the Oneness of Allâh - Islâmic Monotheism) with sure knowledge, I and whosoever follows me (also must invite others to Allâh i.e to the Oneness of Allâh - Islâmic Monotheism) with sure knowledge. And Glorified and Exalted be Allâh (above all that they associate as partners with Him). And I am not of the Mushrikûn (polytheists, pagans, idolaters and disbelievers in the Oneness of Allâh; those who worship others along with Allâh or set up rivals or partners to Allâh)." (12:108)

Say (O Muhammad-peace be upon him): "Verily, my Salât (prayer), my sacrifice, my living, and my dying are for Allâh, the Lord of the 'Alamîn (mankind, jinns and all that exists).
"He has no partner. And of this I have been commanded, and I am the first of the Muslims."
Say: "Shall I seek a lord other than Allâh, while He is the Lord of all things? No person earns any (sin) except against himself (only), and no bearer of burdens shall bear the burden of another. Then unto your Lord is your return, so He will tell you that wherein you have been differing." (6:162-164)

Invite (mankind, O Muhammad-peace be upon him) to the Way of your Lord (i.e. Islâm) with wisdom (i.e. with the Divine Inspiration and the Qur'ân) and fair preaching, and argue with them in a way that is better. Truly, your Lord knows best who has gone astray from His Path, and He is the Best Aware of those who are guided. (16:125)

Let there arise out of you a group of people inviting to all that is good (Islâm), enjoining Al-Ma'rûf (i.e. Islâmic Monotheism and all that Islâm orders one to do) and forbidding Al-Munkar (polytheism and disbelief and all that Islâm has forbidden). And it is they who are the successful. (3:104)

Verily, those who conceal the clear proofs, evidences and the guidance, which We have sent down, after We have made it clear for the people in the Book, they are the ones cursed by Allâh and cursed by the cursers.
Except those who repent and do righteous deeds, and openly declare (the truth which they concealed). These, I will accept their repentance. And I am the One Who accepts repentance, the Most Merciful. (2:159-160)