|The phrase “the righteous person lives by his faith” means that the greater a person’s faith, the more alive, inspired, and vibrant he is.
When a person believes that God exists not only somewhere in the heavens above but is here with us and that there is truly nothing besides Him, that is the sole source of his joy and vitality.
The purpose of the creation of man and all the worlds is for God to have a dwelling place below, which, as was noted above, is our personal, subjective awareness that God is with us.
When a person attains this awareness that God is with him, that God is his life and that there is nothing besides Him, he fulfills his part in the purpose of his being created and of the creation of all the worlds.
Rabbi Adin Steinsaltz