Heaven can also be referred to as the kingdom of God. The kingdom of God is the realm of God's governmental administration. It is that sphere where God reigns absolutely. There is a dimension of the kingdom that has to do with location while the other is a realm. Today the kingdom of God is where God exercises His authority without restraint.
There is a side in the gospel of the kingdom that has to do with preaching the gospel of the kingdom. There is also the one that has to do with the demonstration of God's power. Jesus preached and demonstrated the kingdom. One of the prominent signs of preaching the gospel of the kingdom of God is casting out devils. When devils are cast out the kingdom of darkness is displaced and the kingdom of God is established.
Matthew 12:28 But if I cast out devils by the Spirit of God, then the kingdom of God is come unto you.
Everything that came into the earth as a result of sin needs to be displaced. This includes sickness, diseases, poverty, lack and all negativities of life. God made us gods on earth and He did so so that we can exercise our authority on earth.