eternity past, God had planned history with His Son having a bride, a companion that would co-reign with Him and enjoy Him forever. That is the eternal purpose of God in creating a bride for His Son.
If you read the Scripture from cover to cover, you would discover that God teaches us in a variety of different ways. Sometimes God uses powerful word pictures, sometimes He uses symbols, sometimes He uses examples of people both good and bad. Sometimes God uses a direct word, an authoritative word, sometimes He uses examples from nature, like a tree planted by the rivers of water that will not cease to bear fruit.
This book highlights how God gave us an example of an ancient Jewish wedding ceremony that correlates with Christ, the Bridegroom, and His bride the church. From the father choosing a bride for his son, paying the bridal price, the bridegroom snatching his bride and bringing her to the bridal chamber, and then finally co-reigning with him in their household with him as the head. It is absolutely amazing the correlation between the two. What was a mystery to the Jews has been revealed. The mystery was that both Jew and Gentile called the church would be the bride of Christ.
The bride of Christ is describing the kind of relationship we can have with Jesus. God is seeking willing lovers, who would voluntarily seek His heart, voluntarily surrender to Him, and voluntarily love Him with all their heart, soul and mind, and strength.