Text. Psalm 15.
Catechism Q.112. What is required in the ninth commandment? A: I must not give false testimony against anyone, twist no one’s words, not gossip or slander, nor condemn or join in condemning anyone rashly and unheard. Rather, I must avoid all lying and deceit as the devil’s own works, under penalty of God’s heavy wrath. In court and everywhere else, I must love the truth, speak and confess it honestly, and do what I can to defend and promote my neighbour’s honour and reputation.
In Q112 the Catechist discusses a real flaw in our fallen human nature, – our innate impulse to tell lies. He is expanding and explaining the words of the ninth commandment, “Thou shalt not bear false witness against thy neighbour.” I mean who would do that? The answer is simple! ME! And you. And if you say that you wouldn’t ever bear false witness against your neighbour, you are a liar!