Why does God call rest the "jewel" of His blessings in "The Pulley"?

In "The Pulley", rest is the shining jewel of all the gifts and blessings God bestows upon his human creations. As God is bestowing these blessings, however, he realizes that if he fully bestows the gift of rest upon his creations, they will be so fully in peace and comfort that they will no longer need God or seek Him.
As such, rest is the coveted jewel of the blessings that is bestowed partially and temporarily, but not fully, upon humans. This way, humans are bound to always seek peace and true rest—not in nature of in the earthly world but in the heavenly world of God.
This disturbing poem truly conveys how conditional and abusive of a relationship the creator has with its creations. Though the creator has the ability to give its creations true peace and happiness, the creator chooses not to, because that would render the creator as less needed by humans and therefore less powerful and, ultimately, less in control of humanity.