Dr. Mitchell continues in 1st Peter 3 verses 21 and 22. In this context, Peter is writing about Jesus Christ. Here in chapter 3 verses 18 thru chapter 4 verse 1, Peter is writing about Jesus, His death, burial, resurrection and His seat at the right hand of God with angelic beings having been made subject to Him.
Then in verse 22, we see Jesus in heaven seated at the right hand of God. He is seen as having all angelic spirits subjected to Him. Jesus is in charge of all angelic beings. They are ministering spirits sent out to minister to the believer, as Hebrews chapter 1 verse 14 tells us.