Where in the Bible do you find the position of the church age believer taught?

Les explains that all these letters of Paul are called the church epistles, but Ephesians, Philippians, Colossians, and Philemon are normally referred to as the prison epistles because they were written while Paul was in prison in Rome shortly before he was martyred. In these prison epistles, there is no single mention of the Old Testament, no reference to the Jew, because everything has flowed into the teaching of the Body of Christ, in which there is no distinction between Jew and Gentile. Les emphasizes that this is strictly church ground, and no other portion of Scripture is so profoundly directed to the position of the church age believer. He notes that these things are not found in the Old Testament, the four Gospels, Acts, or even in Paul's letters of Romans and Corinthians with this emphasis. He also points out that about ninety times in just six chapters, the prepositional phrases 'in Him,' 'in Christ,' and 'in Whom' appear, all depicting our position.