Paul describes how the people he was writing to were in a terrible spiritual condition before they believed in Jesus Christ. He says they were like dead people in their relationship with God (see 2:5; Colossians 2:13). This spiritual death happened because of their disobedience and sins. They regularly did things that went against God's will and broke his commands.
Paul explains that their sinful actions were influenced by the power of the devil. The devil was working in their lives, leading them away from God and toward wrongdoing.
Because of this situation, the people Paul wrote to were under God's judgment. They were condemned along with everyone else in the world who did not follow God.