Here is a fascinating exchange:

The seventy-two returned with joy, saying, “Lord, even the demons are subject to us in your name!” And he said to them, “I saw Satan fall like lightning from heaven. Behold, I have given you authority to tread on serpents and scorpions, and over all the power of the enemy, and nothing shall hurt you. Nevertheless, do not rejoice in this, that the spirits are subject to you, but rejoice that your names are written in heaven.” (Luke 10.17 – 20, ESV)

The usual take on this is that when Jesus “saw Satan fall like lightning from heaven,” he was talking about their casting out demons. But I heard an old pastor in a small group setting give a different interpretation: He said, “The 72 were proud and excited about what they had done. Jesus warned them of pride. ‘I saw Satan fall like lightning from heaven.’ Why did Satan fall? Because of his pride. ‘Don’t rejoice that the spirits are subject to you but rejoice that you’re on the team.’”

But Jesus rejoiced that so many “little children” – probably the ordinary people who were following him – were getting it. 

In that same hour he rejoiced in the Holy Spirit and said, “I thank you, Father, Lord of heaven and earth, that you have hidden these things from the wise and understanding and revealed them to little children; yes, Father, for such was your gracious will. All things have been handed over to me by my Father, and no one knows who the Son is except the Father, or who the Father is except the Son and anyone to whom the Son chooses to reveal him.” Then turning to the disciples he said privately, “Blessed are the eyes that see what you see! For I tell you that many prophets and kings desired to see what you see, and did not see it, and to hear what you hear, and did not hear it.” (Luke 10.21 – 24, ESV)