What does Isaiah 11:9 mean?

Isaiah has been painting the picture of life under the rule of Israel's future king (Isaiah 11:1–8). The one who will become known as the Messiah, the one Christians know as Jesus, the Son of God. Isaiah writes that "they" will not hurt or destroy in "all of His holy mountain." This raised the question of who "they" are, for the purposes of this verse.

Those who understand the previous verses to be about the animal kingdom see "they" as referring to predatory animals. These animals will stop hunting and killing, being changed in their very being during the rule of Christ on earth. Those who understand Isaiah to be picturing animals as representative of peoples and nations read "they" to refer to those formerly aggressive nations. Those that existed to kill and conquer the earth (Isaiah 11:6–8).

In either case, all such hurting and killing and conquering will cease once the Messiah sits on the throne of the world. Why will it stop? They will be filled with the knowledge of the Lord. Peace will cover the earth because the world will finally and fully understand who God is and be in relationship with Him through the Messiah, who is Christ.

All attempts to secure global peace in any other way will ultimately fail. There is no system of government or control that can fully unite the peoples of the world together. Certainly not for any lasting period. The only thing that will ever bring true peace and interconnectedness to the world is when the knowledge of the Lord and trust in Jesus, covers the earth. That's the only and final path to global unity—and only Christ, Himself, will be able to achieve it.