Should Christians worry about bringing in the Kingdom?

In the New Testament there are two kingdoms that are talked about, the kingdom of heaven and the kingdom of God.  The kingdom of God is a spiritual kingdom that believers are put in through faith and God’s grace once they have accepted Christ (Luke 17:20-21, Romans 14:17, 1 Corinthians 15:50).  The kingdom of heaven is a physical kingdom in which Christ will rule on the earth for 1000 years (Daniel 7:13-14, Matthew 3:1-2, Acts 1:6, Revelation 20:4).  It is not up to us as Christians to bring in any kind of kingdom.  Christ will bring in His kingdom on the earth at the end of the Tribulation period; we won’t even be on the earth at this time.  The kingdom of God is not something that can be brought in physically by anyone, but one is made a part of once he is saved.