Isaiah 62:5
For as a young man marrieth a virgin, so shall thy sons marry thee: and as the bridegroom rejoiceth over the bride, so shall thy God rejoice over thee. For as a young man marrieth a virgin, so shall thy sons marry thee: and as the bridegroom rejoiceth over the bride, so shall thy God rejoice over thee.
The first half means that Zion's sons are joined to her as a young man is joined to a virgin in marriage. The verse uses marriage to portray a tender, sacred, close and joyful bond in which God rejoices over Zion and His people as a bridegroom rejoices over his bride, with Zion and her land restored to loving union with Him. That same rejoicing is the joy of a bridegroom over his bride belonging to the peaceful kingdom of the Messiah.
In that restoration Zion and her land are no longer termed Forsaken and Desolate. Instead she is called My Delight and her land Beulah, meaning married. In comforting Zion God makes her waste places, wilderness and desert like Eden and like the garden of the Lord. At that time He also gives her the glory of Lebanon and the excellency of Carmel and Sharon.
This rejoicing belongs to the peaceful and long-desired kingdom of the Messiah, established under the whole heaven at Christ's coming. That time is the restitution of all things, when the long rule of evil is broken. The joy is part of Zion's renewed honor and salvation through Christ's work through His followers, and belongs to the people who remain faithful. The gladness points forward to the day when Christ will bring His bride home to the Father's house, when the redeemed will sit down with the Redeemer at the marriage supper of the Lamb.
The portrayal of God's bridegroom joy over Zion gives reason to praise God. The bridegroom joy also describes God's joy over the returning sinner, which is full of love and gladness. The Lord's joy at the return of those who have left Him shows His continuing love and His readiness to receive repentant sinners with joy.