Jesus had sent out his disciples to the various villages where he was going to proclaim that the Kingdom of God was near. When he did so, he gave them the power to heal the sick, to raise the dead, and to drive out demons and when the disciples returned, they rejoiced together because the disciples were successful in their mission and were able to drive out demons, just as Jesus had been doing and gave them the power to do.
Jesus even went on to say that he saw Satan fall like lightning from heaven. He saw Satan’s downfall in the midst of the work that the disciples were doing.
But then Jesus goes on to explain to the disciples that it is important that they rejoice for the right things. Yes, they have the power to drive out demons, but this isn’t the main reason that they should be happy and rejoice:
However, do not rejoice that the spirits submit to you, but rejoice that your names are written in heaven.
Luke 10:20
Jesus knows that it is easy for people to be confused. We get excited about the possibility of riches. We get excited about popularity and fame. And we get excited about power. These are the things that our hearts easily chase after, and Jesus knows this to be true.
I think that this is why he tells his disciples that they should not rejoice that the spirits submit to them, but instead that they should be excited that they will be in heaven with him.
To be with him, to have eternal life, to be able to live forever enjoying to the presence and glory of God – these are the things for which we should rejoice. Money, fame, and power are all fleeting. We will one day die. All of us. 100% of us. And the money, the fame, and the power that we have experienced here on earth, or not, will mean nothing. Absolutely nothing. But those things that have eternal significance will be the things that will live on because the life of our spirits will be eternal, in heaven with Christ.