The Nefesh HaChaim writes in Chapter One: "A man of Israel must understand, know, and establish in his mind and heart that every detail of his deeds, speech, and thoughts, at every second and time, all rise up according to their root source to influence the most exalted worlds. Therefore, when a man entertains an impure, licentious thought in his heart, G-d forbid, he in effect brings a prostitute into the most exalted, celestial Holy of Holies, giving strength to the forces of impurity and evil in this transcendently holy place, to a greater extent than the impurity caused by Nebuchadnezzar and Titus when they brought a prostitute into the Holy of Holies in the Temple sanctuary on earth."