A Lesson Book for Angels
Did you know that part of the reason you are a Christian is to be a lesson book for Angels? Paul had just described in Ephesians 3 how God was seeking sinners from the Jews and Gentiles and making them the children of God. Their sins are forgiven and they are adopted as the sons and daughters of God. God's purpose was not only to bring children into the family of God but to illustrate also his grace to spirit beings.
10 in order that the manifold wisdom of God might now be made known through the church to the rulers and the authorities in the heavenly places—(Eph 3:10).
God, instead of giving lectures on grace and kindness and mercy and goodness, illustrates it in a living way through what the church is experiencing. There is no mercy or grace for fallen Angels so the only way spirit beings can learn about the mercy of God is to observe the church and God's ways on Earth. Your salvation has an angelic dimension: you illustrate to Angels the grace of God.