Christ saves us. The church is the body of all people who have been saved by the blood of Jesus. The terms are used interchangeably. The kingdom is a fundamental part of the gospel. People who say we should preach Christ, not the church, need to consider these passages.
Darkness is a symbol of evil.
In the kingdom we are qualified to partake of the inheritance of the saints, because Christ redeemed and forgave us. The kingdom now exists. It is the church. And all who have been saved from the power of darkness are citizens in it. When we understand the terms used to describe the church, we will understand that all saved people are in the church.