"Those who trusted in Cush and boasted in Egypt will be dismayed and put to shame." NIV translation
The northern kingdom of Israel had joined with Egypt in the battle against the Assyrians. They all tried to get the king of Judah to join the alliance. Isaiah was warning them that they should not trust in any nation to protect them but instead should trust in God.
The same thing holds true for us, as Christians, and for the land of Israel today. Jesus is our deliverer and we must always remember that. In Revelation, we are told of the day when a rider will come on a white horse (see Revelation 6). This rider will bring a supposed peace to a troubled world but it is a false peace just as the northern kingdom had falsely trusted in Egypt and Cush to help them.
"In that day the people who live on this coast will say, 'See what has happened to those we relied on, those we fled to for help and deliverance from the king of Assyria! How then can we escape?'" NIV translation
When the people that they had trusted in are led away in shame, the people will lose hope.
It is the same with those who will trust in an earthly leader in the last days. At the mid-point of a peace treaty, they will realize that it was a false hope and the world will find itself enslaved. The only way to avoid this is to trust in our Deliverer and His provision for our peace with God.
We all have a walk of faith that is set before us and each walk begins with a first step. That first step is accepting Jesus as our Deliverer.