What one makes of Isa 11 depends on the general prophetic scheme one adopts concerning eschatology, whether, preterist, historicist, futurist or idealist/spiritual. Regardless of which of these one adopts, several points about this prophecy are clear:
- it concerns (at least in part) the return of the Jews to Jerusalem after the Babylonian captivity under Zerubbabel
- it concerns the work and ministry of the future Messiah
- if "for the earth will be full of the knowledge of the LORD as the sea is full of water" then this can only occur after Jesus' return
Thus, it appears that Isa 11 is a combination prophecy about at least three events:
- The return of the Jews under Zerubbabel
- The first coming of Jesus in Bethlehem and His ministry
- The second coming of Jesus and the kingdom of God
That is, the actual event of the return of the Jews under the descendant of Jesse, Zerubbabel, is used as a prophetic model of the work of Messiah at His first and second advents. Note the text of Isa 11:6-9
6 The wolf will live with the lamb, and the leopard will lie down with the goat; the calf and young lion and fatling will be together,
and a little child will lead them.
7 The cow will graze with the bear, their young will lie down together, and the lion will eat straw like the ox.
8 The infant will play by the cobra’s den, and the toddler will reach into the viper’s nest.
9 They will neither harm nor destroy on all My holy mountain, for the earth will be full of the knowledge of the LORD as the sea is full
None of this has ever occurred, and will never occur, until the LORD establishes the literal, visible kingdom of God following His return to earth. In such a scenario, the New Jerusalem on the new Mt Zion (Rev 21) will be the capital of God's government and only then (compare Heb 8:11) will everyone "know the Lord".
Historically, the earthly city of Jerusalem has been one of the most fought-over places on earth with untold bloodshed in countless battles. However, when the New Jerusalem is established:
They will neither harm nor destroy on all My holy mountain, for the
earth will be full of the knowledge of the LORD as the sea is full of
water. (Isa 11:9)