Have you noticed how accessible junk food is in our culture while healthy nutritious food is more difficult to come by? For instance, in full disclosure, I would rather have an oreo cookie instead of an apple. Why? Why do I long for Oreo cookies when I know they are nothing more than a substitute cookie with artificial flavoring that will never be able to satisfy? Jesus brings up a similar point regarding the appetites of our hearts in His sermon on the mount. He is going to point out what it is that makes God's kingdom citizens satisfied in an unsatisfying world.