Holy things cannot be acquired "for free," that is, without proper effort. This is why Abraham insisted on paying for the transfer of the property, thereby elevating it into the realm of holiness.
Similarly, each one of us has been assigned a portion of the world that we are responsible to make holy. We must do this at "full price," with hard work and effort. Even those of us who find it easy to study the Torah and observe the commandments must push ourselves beyond the boundaries of our natural inclinations. Only in this way can we achieve our purpose in the world.
—from Daily Wisdom 3