Heidelberg Catechism Lord's Day 43

112. Q . What is the aim of the ninth commandment?
      A. That I never give false testimony against anyone, twist no one’s words, not gossip or slander, nor join in condemning anyone rashly or without a hearing.
Rather, in court and everywhere else, I should avoid lying and deceit of every kind; these are the very devices the devil uses, and they would call down on me God’s intense wrath.
I should love the truth, speak it candidly, and openly acknowledge it.
And I should do what I can to guard and advance my neighbor’s good name.