God's kingdom is in sovereign dominion and power. The kingdom is in the power of the Holy Spirit (Romans 14:17). The King of the kingdom is Jesus our risen Lord (1 Corinthians 12:3). He is the King of Kings and Lord of Lords (Revelation 19:16).
After his resurrection, Jesus said, All power is given unto me in heaven and on earth (Matthew 28:18). He came into this present evil world to defeat sin, Satan, and death, through the cross and the resurrection. The power of evil was broken, yet the victory has not come in all of its fullness. The warfare rages, as the kingdom of light attacks the kingdom of darkness. However, the complete defeat of evil will only come at the return of Christ in kingdom power and great glory (Luke 21:27; 1 Corinthians 15:24-28).
God's kingdom is in the power of the Holy Spirit. We enter the kingdom through new birth, by faith in the Lord Jesus Christ (John 3:5-8; 1 John 5:1). Only through the power of our Lord Jesus can we break free from the control of the evil one (1 John 5:18-20). Those who are born of the Spirit see kingdom power in the gospel of Christ (Romans 1:16).
God's kingdom shall come in sovereign power at the second coming of Christ. Jesus taught us to pray: Our Father in heaven ... Your kingdom come. Your will be done on earth as it is in heaven (Matthew 6:9-10). God's kingdom continues to come until that day when King Jesus returns. Then, kingdom power and authority shall bring the final and total victory. That means God's kingdom shall be revealed to all in sovereign power and glory.