Peace Between Jew and Gentile Through Christ. All Built into the Lord's Holy Temple. And you hath he quickened. In the closing part of chapter 1 Paul has described the mighty working of the Divine power in raising Christ from the dead, and his exaltation to the right hand of God. Dead in trespasses and sins.
Spiritual death is meant.
By their trespasses and sins they were separated from God. To be without God is to be in death. According to the course of this world. You lived in trespasses and sins, in accordance with the spirit of the world. The prince of the power of the air.