Answer
Isaiah 11 speaks of a time when the Messiah will rule His earthly kingdom; it will be a time when there will be no hurt or destruction on God’s “holy mountain” because the entire earth will be full of the knowledge of Yahweh (Isaiah 11:9).
In Isaiah 11, we see that the Messiah will be from the line of Jesse (Isaiah 11:1), and the Spirit of the Lord will be with the Messiah (Isaiah 11:2). He will judge righteously and faithfully (Isaiah 11:3–5). During His rule, natural enemies will no longer be at war—the wolf and lamb will no longer be predator and prey, and the same will be true of the leopard and the goat and the lion and the calf—in fact, these animals will be so docile that a little boy will lead them. Of course, such a situation is impossible in our current conditions (Isaiah 11:6).
The prophecy continues. Not only will there be peace among the animals, but there will be peace between the animal kingdom and humanity: even a child of nursing age will be able to play fearlessly near a cobra, and a young child can be near a viper’s den without danger (Isaiah 11:7). Because all the earth will know the Lord, there will not be injury or destruction anywhere on God’s holy mountain (Isaiah 11:9).
The same mountain is mentioned earlier in Isaiah: “It shall come to pass in the latter days That the mountain of the Lord’s house Shall be established on the top of the mountains, And shall be exalted above the hills; And all nations shall flow to it” (Isaiah 2:2, NKJV). Jeremiah identifies Jerusalem as the site of the Messiah’s throne: “At that time they will call Jerusalem The Throne of the Lord, and all nations will gather in Jerusalem to honor the name of the Lord” (Jeremiah 3:17).
God’s holy mountain is identified in its first Old Testament reference as Zion (Psalm 2:6) and again by the psalmist as the city of God (Psalm 48:1). The Messiah will return to Zion and dwell in Jerusalem, which will be called the City of Truth, and God’s mountain will be called the Holy Mountain (Zechariah 8:3). The prophet Zechariah describes the Messiah’s return to the Mount of Olives (which is in front of Jerusalem on the east) as literally a mountain-splitting event, and Yahweh will rule over all the earth from Jerusalem (Zechariah 14:4, 9, 16–21). Mount Zion, Jerusalem, is God’s holy mountain and is where the Messiah-King will be installed (Psalm 2:6).
It is possible that the reference to God’s holy mountain encompasses more than just Jerusalem, however. In the Old Testament Zion is used as more than a name for the city of Jerusalem (Isaiah 40:9); it is also used to refer to the land of Judah (Jeremiah 31:12) and the nation of Israel as a whole (Zechariah 9:13). Many commentators consider God’s holy mountain to extend to the whole hill country in the land of Israel. Others see “God’s holy mountain” as a way of describing the whole earth during the reign of Christ—indeed, Isaiah 11:9 mentions the whole earth being full of the knowledge of God, so the whole earth will enjoy the effects of Christ’s rule.