Queries on Ephesians 3

Ephesians 3
Listen from:
6. Does εἴναι here express not the design but the subject and purpose, “that the Gentiles are?”
8. Is it just to draw from τῷ ἐλαχ. π. ἁ. not only the remembrance of the former persecution of the church but of his own sinful nature (1 Tim. 1:15, εἰμί, not ἠν)?
9. How are we to understand ἀπὸ τῶν αἰώνων compared with Rom. 16:25 Cor. 2:7, as well as verse 11 following?
21. Does the last phrase take in eternity as well as the millennial age?