While it should be no Bible mystery that Christians will judge the angels, it is a Bible mystery as to the basis of that judgment! Here is the only reference to this mysterious event:
Do you not know that we will judge angels? How much more the things of this life! (1 Cor 6:3)
That angelic judgment indicates the free will angels have, which has led some to sin as mentioned in 2 Pet. 2:4. Apparently, the overcomers will become aware of the angels’ past activities from the vantage point of that judgment. Could that activity be connected with their ministering to the heirs of salvation (the Christians) themselves?
Are not all angels ministering spirits sent to serve those who will inherit salvation? (Heb 1:14)
Perhaps, but we can’t be sure. Without doubt, exciting and surprising times are ahead for the righteous who endure, including the mysterious judgment of angels — whatever that will be! The important thing now for the Christian is to live holy and continue in the faith (Col. 1:23). To die in Christ is gain for the Christians living for Christ (Phil. 1:21) for we go home to be with our spiritual family. Remember 1 Cor. 2:9.