Paul takes a side journey in v. 2 after he begins to pray for the Gentile believers in v. 1 This parenthesis goes through verse 13. He wants the Gentile to know that he is imprisoned in Rome because of his ministry to them, but it is Jesus Christ who holds the key. Paul wants his new
Brothers and Sisters in Christ to understand that God planned their conversion before time began, planned the filling up of the Church with Jew and Gentile as well. And with those plans come great spiritual riches.
