Consider such example...
The world is the restaurant. God is the owner, of'course. Hebrews are the staff and nations are the clients.
As anyone will tell you, a restaurant is only as good as the staff that is working there. If the staff is polite and friendly there are usually no problems and everyone is happy.
At the same time, if the staff is rude and has a superiority complex, such restaurant would not be a very nice place to eat.
Hebrew nation is called the "kingdom of priests" (Exodus 19:6), so Hebrews must set the example and live the highly moral and a spiritual life.
We, Hebrews, are like the eldest brother among all the nations. The example we set will be followed by others so we must watch out what we do as a nation and as individuals.
This is why we must live ONLY by the Written Torah because it is the ONLY Law that was given to the Hebrews by God. If we will continue to follow other gods and add to the Torah, we will only invite trouble, hate and anti-semitism.
The only way for the Hebrews to live in peace is to take on the role of the WISE and RIGHTEOUS leaders of the nations and set an example that will be coveted and followed.