Luke 10:20

“Nevertheless do not rejoice in this, that the spirits are subject to you, but rejoice that your names are written in heaven.”

However, while they may rejoice in the spirits being subject to them they should not make this the main reason for their rejoicing, for it is theirs because of something in which they should rejoice even more. And that is that they belong to Him and are therefore citizens of Heaven, with their names written in the citizenship roll of Heaven. They are recognised citizens under the Kingly Rule of God. That is why as His heavenly ambassadors they been able to defeat Satan. We may see this citizenship roll as the equivalent of the Lamb's book of life where the names of His own are written from the foundation of the world (Revelation 13:8; Revelation 17:8; Revelation 20:15; Revelation 21:27; Philippians 4:3). It contains the names of all who are His.

Jesus was aware of the danger of their seeing power over evil spirits as too important. It could become their fetish. They must rather see it in its place as a secondary result of what they are in Him. Primary must always be their relationship with and knowledge of Him which has resulted in them being heavenly citizens. They should thus primarily rejoice because they are men of the Spirit (John 3:1). As He will go on to point out, their ability to cast out evil spirits in His name, comes from their knowledge of Him in their inward hearts. Were they to lose that the spirits would no longer be subject to them