"The purpose of the creation of every Jew and of all the worlds is to make a dwelling place for G-d in this world." (Tanya, Chapter 33)
The reason why G-d made each Jew and why He created the whole world, is so that by following Torah and Mitzvos, we can make ourselves, and our homes, and the world around us a dwelling place for G-d, where He will live, just as we live in our own homes.