One of my Scripture professors at St. Louis University, Fr. Frank Cleary, was one of the first Americans to travel to the Soviet Union in the 70s when that highly secretive country opened its doors to tourists. When he returned, we pumped him with questions about his experiences. He mentioned that the scariest part of his trip happened when he was leaving the Moscow airport for the return flight to America.
Before he was permitted to board the plane a security person held his passport picture next to his face for what seemed a very long time. He continually looked back and forth at the photo and Frank, checking various facial features to make certain the person who was about to leave the country was actually the same person who had arrived there a few days before, and not a fugitive trying to escape the country with a fake passport. Finally convinced the person in the picture was actually the person boarding the plane, he let Frank leave.
Most Christians employ a parallel process when they speak about Jesus as Messiah. We have an idea there's a picture of the Messiah in the Hebrew Scriptures that we can hold up next to Jesus to identify him as the real McCoy that Jews had been expecting for centuries. There's just one problem: there's no one picture of the Messiah in the Hebrew Scriptures. If we used that means of identification, Jesus would never be permitted to board the plane.
There are many messianic pictures in the Hebrew Scriptures, none of which completely mirrors Jesus as Messiah. Each generation of Jews conceived of the person who would eventually save them in concepts different from the prior generation. As their needs changed, so did their idea of Messiah change. Contrary to common belief, there's no one consistent picture.
Isaiah, for instance, in today's passage conceives of the Messiah in terms of a king from the family of David. Like his regal ancestor, this new king will be "a sprout from the stump of Jesse." But he'll differ greatly from some of the 8th century BCE kings the prophet has recently encountered. Because he's open to Yahweh's spirit, he'll create a world in which natural enemies will become friends, making certain that "the earth shall be filled with knowledge (experience) of Yahweh."
Though Paul believes Jesus will eventually create the end results which Isaiah expects of a royal Messiah, the Apostle brings in an element which the prophet seems to ignore: the community.
Unlike Isaiah's Messiah, the risen Jesus isn't going to bring about this new world all by himself. He's counting on us to play an essential role in its creation. As Paul reminds the Christian community in Rome, it's up to us to "think in harmony with one another." Among other things, that means we have to "welcome one another as Christ welcomes (us.)"
And especially during Paul's ministry, the group many Jewish Christians had the most problem welcoming was Gentiles. Though Isaiah envisioned non-Jews seeking out Yahweh, the Apostle envisions Jewish Christians taking the first step and seeking out Gentiles as equal partners in the salvation Jesus offers. Only when all God's people relate correctly with one another will God's peace become a reality.
That seems to be part of the "good fruit" John the Baptizer expected all God's people to produce.
True followers of Jesus long ago came to understand that their Messiah was only part of the show. They and their relations with others were the rest of the show. No wonder St. Augustine always handed the Eucharistic bread to people with the reminder, "Receive what you are: the Body of Christ (the Messiah)."