Matthew 23:22

22 Or somebody may make a promise by heaven. Then he is making a promise by the place where God sits and rules. So he is making a promise by the name of God himself.

23:16Jesus meant that the teachers of God's Law and Pharisees did not understand about the kingdom. They were like men who could not see. They did not know God's way, but they were trying to teach it to other people.
23:22Perhaps a person wants to make a promise very strong. So he uses someone's name to make the promise stronger. Jesus says that we should not do this. If we make a promise, people should be able to trust us to do what we have said.