The Lord says: "For Zion's sake I will not keep silent, for Jerusalem's sake I will not remain quiet, till her vindication shines out like the dawn, her salvation like a blazing torch. The nations will see your vindication, and all kings your glory; you will be called by a new name that the mouth of the Lord will bestow." (Isaiah 62:1-2)
Israel has had many enemies throughout the ages. All of these enemies have been Gentiles: "the nations". Even in our own day, Israel has many enemies who would like to see her wiped off the map. But the Lord has always promised to preserve descendants of Jacob and, in the eternal kingdom, to make Jerusalem the capitol city of the whole world---the city from which the King of kings will reign forever.
Every time He has rescued Israel from an enemy, the world has seen it. No king or regime has ever been able to eradicate the descendants of Jacob from the earth or to completely destroy the nation. Even nations that don't acknowledge the Lord as their God have had to admit that He has provided for and protected the descendants of Jacob and the Promised Land.
"You will be a crown of splendor in the Lord's hand, a royal diadem in the hand of your God. No longer will they call you Deserted, or name your land Desolate." (Isaiah 62:3-4a) The land desolated by ancient enemies would not remain uninhabited by the people who whom the Lord gave the land when He brought them out of Egypt. Many would return from captivity to resettle it. In more modern times, since the reinstatement of Israel as a sovereign nation in 1948, many more Jewish people from all around the world have returned to the land. In a future time, it appears that under the Messiah's eternal reign there will be more people returning than ever before---perhaps all of the people on earth of Jewish heritage. The borders of the Promised Land were intended to be quite large, as outlined earlier in our study of the Old Testament, but the people never conquered and took possession of all of it. But in the Messiah's kingdom all of the land outlined in the Old Testament will be the nation of Israel, allowing for a great number of Jewish people to live there.
The Lord is going to exchange some old names for new names. The land will no longer be able to be accurately called "Deserted" or "Desolate". In exchange for these terms the Lord will call it something else. "But you will be called Hephzibah, and your land Beulah; for the Lord will take delight in you, and your land will be married. As a young man marries a young woman, so will your Builder marry you; as a bridegroom rejoices over his bride, so will your God rejoice over you." (Isaiah 62:4b-5)
The name "Hephzibah" means "He delights in her", and the name "Beulah" means "married". There are many occasions in the Bible when the Lord refers to Israel (the people as a whole) as His wife. When so many of the citizens fall into idolatry, He compares them to an unfaithful wife. In the Old Testament we've seen Him stating His intention to separate from this wife for a while due to her adultery against Him, meaning He intends to allow her to be conquered and carried away for a time. But a day is coming when He will never again find occasion to be angry with her. He will delight in her as a man delights in the woman he loves. He will join Himself with her forever, never again to be parted from her.
A young man who is about to be married thinks his bride-to-be is the most beautiful woman on earth. He loves her so much that he only has eyes for her. He makes his vows to live with her in fidelity his entire life. The Lord is making vows like this to Israel. He thinks she is beautiful, so beautiful He finds her continually a delight to His eyes. He intends to protect her and be with her forever.