At the end of the 8th century, the prophet Isaiah warns Judah not to trust in alliances with neighboring nations. Judah should trust God. Isaiah expands on one important reason---God will destroy those nations. Rather than trusting in any nation that God will destroy, Judah should trust in God. When it comes to Judah's powerful Southern neighbor, Egypt, another reason is that Egypt will ultimately turn to God. If Egypt will turn to God, then Judah has no reason to turn to Egypt for help against Assyria. At the end of chapter 19, Isaiah writes (v. 23):
In that day shall there be a highway out of Egypt to Assyria, and the Assyrian shall come into Egypt, and the Egyptian into Assyria, and the Egyptians shall serve with the Assyrians.
"Highway" is a favorite metaphor in Isaiah for the removal of alienation and separation. God wanted Judah to tear down her highways to Egypt and Assyria, so that some day He could build a highway between Egypt, Judah, and Assyria. The highways that we build, the alliances that we make, that we think will change things for our good, are actually stopping any kind of real unity or peace.
The application to the church is to stop building highways with the world, with disobedient brethren, and with false doctrine. We won't help the world, the brethren, or the doctrine by keeping a highway, an alliance, or fellowship with any of them. We will never have unity or peace with any of them, even if a Miss America contestant earnestly desired it. The Bible is full of paradoxes, and this is another one. The barriers between us and them, good fences, are what will bring about the very thing that we think will result from building a highway. This might seem like foolishness to you, but to God, it's His power. He is glorified and we get to please Him by faith.
In the end, Egypt and Assyria will serve the Lord. You can see that in v. 23 above. The "Egyptians shall serve with the Assyrians." They won't serve because of some strategy by Judah to break down the barriers between them and her. They will serve God because Judah has torn up her highways between these neighboring nations. Our ministry to the world is lessened by using its music, its methods, and continuing an alliance with it. Scripture teaches and history has shown that these relationships we build do not result in greater ministry, but in our own corruption and then punishment.
We find churches today utilizing the same worthless and destructive ideas as Judah when powerful Assyria became a threat. They build highways to Egypt to make it easier for a successful association. They think that if we lower our music, dress, recreation, and entertainment standards, we will have better opportunities to impact the world. "People will want to change if they see that we are willing to compromise." In certain cases they think by engaging the Southern Baptists, compromising evangelicals, and worldly churches and Christians that everything will work out better. After all, there is always strength in numbers, maybe some of their scholarship can rub off on us, and then we'll get the respect that we think we deserve, the same kind of respect that Baruch thought he and Jeremiah should be getting when God told him, "Seekest thou great things for thyself? seek them not" (Jer. 45:5).
Highways make sense to us---access, ease of movement, free flow of information, and opportunities to find common ground. This infrastructure is doomed to failure. God wants us to tear up the highways and wait for Him to build one that Mayor Daley or anyone else will never tear down, well, for at least something like 1000 years.