The 70 Disciples just came back to Jesus from a Mission trip that he sent them on. They were pumped up because they saw the Lord do great things through their hands.
Jesus presented a key of truth to the disciples on that day. He declared something powerful and so amazing which left the disciples with a different persepective. He gave us a glimpse into his God state while in heaven. He remembered when Satan was kicked out of heaven and he was kicked so hard that he fell down like a lighting bolt. I am thinking that being kick by the foot of God is not a good experience. Oh slue foot , the devil, has that experience. He is such a loser.
Jesus was making a statement to his disciples. " Hey guys, I am here to tell you the enemy is defeated. I have given you the authority to overcome him and his minions. You have the power to crushed the enemy's power. Trust me when I tell you that he is powerless."
Jesus gave his disciples a different perspective on life. He had the advantage of knowing just how powerless the enemy really was and is. Just for those brief moments the disciples were allowed to look through the eyes of Christ.