Even though He offers them no redemption, God is, perhaps surprisingly to us, interested in teaching the angels.
For much of the Old Testament, prophets searched and inquired their own prophecies about the grace that would come through the sufferings of Christ and the subsequent glories. All of this good news, which Peter said had been preached to his elect readers, were “things into which angels long to look” (1 Peter 1:10-12).
On the cross Jesus died for those who were dead in their trespasses. He canceled “the record of debt that stood against us with its legal demands. This he set aside, nailing it to the cross.” This is Christ’s work for us. But in doing so He also “disarmed the rulers and authorities, and put them to open shame, by triumphing over them” (Colossians 2:13-15). At the cross God taught the angels a lesson.
There is another lesson still going on. God is bringing to light for everyone what is the mystery of His plan. This “God who created all things” continues working “so that through the church the manifold wisdom of God might now be made known to the rulers and authorities in heavenly places” (Ephesians 3:9-10). Angels learn lessons as God builds His church.
This demonstrating work goes all the way back to Eden. God told the dragon, “I will put enmity between you and the woman, and between your seed and her seed,” and you are going to lose. We usually don’t describe God’s revelation as “smack talk,” but this is divine insult to the serpent. The woman’s seed wins.
For generations God has been talking this way to rebel angels and He continues to make His point by uniting the church in the Dragon-Slayer, our Savior, Jesus Christ.