Who was the first person in the entire world to reach out to help others spiritually? It was Abraham, our father. Why was Abraham so concerned with others' spiritual understanding?
Abraham was unique in two ways. Number one, he knew G-d, and number two, he was extremely kind.
He was so kind that he would go far out of his way to help others. He would set up his tent only where he would be able to reach out to people passing by.
When you know that Hashem is G-d, and you are kind, you will want others to know that there is only One G-d… that Hashem is the Infinite and only G-d there is, was, or ever will be.
The Torah is not merely a history book telling us how good people behaved way back then. It is telling us how good people should behave today.