Isaiah 11:6–8 (NKJV)
6 “The wolf also shall dwell with the lamb, The leopard shall lie down with the young goat, The calf and the young lion and the fatling together; And a little child shall lead them. 7 The cow and the bear shall graze; Their young ones shall lie down together; And the lion shall eat straw like the ox. 8 The nursing child shall play by the cobra’s hole, And the weaned child shall put his hand in the viper’s den.
An end comes to all strife between creatures. Does this mean an end to carnivorous living for all? I'm not sure at this point. Of course, the most important strife that will come to an end, and has already come, is the division between Jew and Gentile. Now, all are justified by faith in Jesus Christ alone and we are all under one new humanity. Under that reconstruction, all other divisions may come to an end. The Prince of Peace brings peace to all human relationships.
And so, the picture of Isaiah 11:6-9 is one of returning to the paradise of Eden. It is a a picture of the whole creation put back into joint (Webb). And verse 9 is climactic. The entire earth and not simply Jerusalem will be the LORD's holy mountain and His Word, His law, His rule will be known, experienced and enjoyed as much as the waters cover the sea.
The spreading of this dominion, peace, and rule of King Jesus began at His first Advent and will continue until His second. Until then, He rules over heaven and all of the earth while sitting at the right hand of God the Father (Psalm 110:1-2).