In Isaiah, we learn that Isaiah’s message was a message of judgement. Along with that judgement was also a rejoicing and worship, as Isaiah was a singing prophet. He would call upon the people of God to sing praises unto the Lord. In the end of times, Isaiah teaches us that there is coming a day in which the land of Judah will sing about what a strong city they have.
During Isaiah’s time, Jesus’ time, and even now, the Jewish people have not been able to sing that they have a strong city, but there is coming a day when they will sing it, as God will destroy their enemies. There will be much rejoicing during that time.