"And Jacob vowed a vow"
This passage explains the story of Jacob in terms of the Sfirot and their interactions. Rabbi Chiya gives an interpretation concerning King David and his fear of the wickedness of the world, "the place where the books of the wicked are opened." Other rabbis add that the pillar of the left, Judgment, is necessary for the subjugation of the Klipot.
Jacob corresponds to the Central Column, the Sfirah of Tiferet, whose position is squarely in the middle of the Tree of Life. Jacob is the balancing force between the Right Column energy of Mercy and the Left Column force of Judgment. Through the Sfirot, the attributes of mercy and judgment are carefully mingled, balanced, and disseminated in the physical realm, in accordance with the interactions of human beings to one another. In our world - signified by King David - wicked forces incite us to inflict judgment upon one another. Through the light of Jacob's soul we can temper our judgment, sweeten it with mercy, and therefore treat one another with compassion and kindness. Doing so produces the same effect in the Upper World, and the Sfirot shower our physical domain with an equal measure of mercy. Reading these passages with a pure heart will set this light in motion.