God has communicated His Divine Revelation to people by means of His messengers throughout history. These messengers told people about God and communicated to them the words of our Lord.

Moses was a major prophet and a leader who freed the Israelites from the oppression of the Pharaoh; he is not only referred in Judaism and Christianity, but also in Islam. God chose Moses to deliver the message to his people to worship one God.

Shema Yisrael Adonai Eloheinu Adonai Echad "Hear, O Israel! The LORD is our God! The LORD is One!" Deuteronomy 6:4

And God spoke all these words:
I am the LORD your God, who brought you out of Egypt, out of the land of slavery.
You shall have no other gods before me.
You shall not make for yourself an idol in the form of anything in heaven above or on the earth beneath or in the waters below.

You shall not bow down to them or worship them; for I, the LORD your God, am a jealous God, punishing the children for the sin of the fathers to the third and fourth generation of those who hate me, Exodus 20:1-5 

For thou shalt worship no other god: for the LORD, whose name is Jealous, is a jealous God: Exodus 34:14