The 9th Commandment

Westminster Shorter Catechism
Q. 76. What is the ninth commandment?
The ninth commandment is: You shall not give false testimony against your neighbor.
Q. 77. What does the ninth commandment require?
The ninth commandment requires us to tell the truth and to maintain and promote it and our own and others’ reputations, especially when testifying.
Q. 78. What does the ninth commandment forbid?
The ninth commandment forbids anything that gets in the way of the truth or injures anyone’s reputation.