G-d created man and his spiritual light shone from the highest to the lowest worlds. But Adam sinned and his two sons, as well. Abraham connected the world to the sefira of chesed on the Right. Isaac connected the world with the sefira of gevura and Jacob connected the world to the center.
When Jacob's descendants received the Torah at Mount Sinai and erected the Tabernacle, the world was finally established, and all the worlds, physical and spiritual, were completed and in harmony again.