Empty Desires and Lust

Lusts of the physical world can be compared to rays of light. When they enter the home, sunrays appear like pillars due to the radiance of the sun. It appears that one can grab these pillars of light. Yet when they are grabbed and grasped, there is nothing in the hand. All the desires and lusts of this world are exactly like this.
(Sichos Haran 6)