Why won't the lamb have to worry about the wolf in the coming kingdom?
In the coming kingdom, when the curse is lifted, the wolf will dwell with the lamb and will not kill it. Instead, the wolf will eat grass, berries, and everything else just like other creatures. Therefore the lamb will not have to worry, because the wolf is going to eat vegetation rather than prey on it.
Les explains that this is the condition after the curse is lifted, as described in Isaiah chapter 11 and looked forward to in Romans chapter 8. He contrasts it with nature today, which labors under the curse, using the illustration of a prairie chicken and a hawk to show how predators stalk and kill. In the coming kingdom, when Christ, the branch of verse 1, rules and reigns, righteousness and faithfulness characterize His reign. Then in the animal kingdom the wolf shall dwell with the lamb; the lamb will not have to worry and the wolf will not kill it, because the wolf will eat grass, berries, and everything else just like other creatures.
The wolf also shall dwell with the lamb, and the leopard shall lie down with the kid; and the calf and the young lion and the fatling together; and a little child shall lead them.
And the cow and the bear shall feed; their young ones shall lie down together: and the lion shall eat straw like the ox.