The Ninth Commandment: People committed to the truth

The Ninth Commandment, Exodus 20:16. This commandment addresses the need for us to speak the truth. We will consider the origin of lying and the blessing of the truth and its ultimate success through the gospel. Additional scripture references: John 8:31-47, Ephesians 4:11-16.
We will consider these four questions concerning the commandment:
1. What is forbidden in this commandment?
2. What duties are required?
3. How has Christ fulfilled it?
4. How can we begin to live it in him?