What does the ninth commandment forbid?

The ninth commandment primarily addresses the importance of truth in our words and actions and emphasizes the protection of an individual’s good name and reputation. Therefore, it forbids any form of bearing false witness or speaking in a way that harms the truth and damages someone’s reputation.

Choosing the option that indicates "all prejudicing of the truth and good name" captures the full scope of what the commandment prohibits. This includes not only lying or spreading falsehoods about others but also any actions or speech that could unjustly harm their reputation. Such a comprehensive understanding recognizes the broader implications of how words and behavior affect the integrity of individuals and the community.

In contrast, focusing only on false witness, actions that spread rumors, or speaking against authority does not encompass the complete essence of the commandment. Each of those options highlights a specific aspect, but they fail to capture the commandment's broader intention to protect both truth and the good name of others fully.