Why do we need to practice gratitude?

Why must you practice gratitude?

As you practice gratitude and acknowledge what you already have, you shift, not only your focus, but also your vibration into the direction of more of the thing you are looking for. You see—

You cannot ask for anything that you do not already have.

—Omni-Emmanuel

John L. Payne, Omni Reveal the Four Principles of Creation, 2001, Findhorn Press, United Kingdom, Chapter 5, Abundance, 66