NOTES for Luk 10:17-24
The Lord's disciples were people just like us. They also argued, were afraid, were vain, were proud... But they knew how to trust. They followed Jesus, leaving everything, although they had no idea what awaited them. They cast out demons and healed the sick, believing that in the name of Jesus a demon would leave and the sick would be healed. They rejoiced like children that it worked.
This very ability - the ability to trust - is what we have lost. We need proof that we can do something; it is not enough for us to know that God thinks we can. In response to God's request to do something that we consider impossible for ourselves, and sometimes simply difficult and unusual, instead of trusting and doing what God asks us to do, we say to God, "Prove to me that I can do it." And when it turns out that yes, I can, instead of thanking God who gave us this opportunity, we boast about our abilities.
There is nothing wrong with rejoicing that we do something well, because when God created the world He said, "It is good," and the ability to create something new has been given to us by God, so we too can sometimes say those words. But we cannot say them without adding, "Lord, I thank You," because without God we can do nothing.