You shall not bear false witness against your neighbour. Ex 20:16
This commandment encompasses false speech in any situation, as well as any attempt or intention to deceive our fellow human beings. The act of intending to deceive is what constitutes falsehood. Falsehood can be conveyed not only through spoken words but also through a glance, a hand gesture, or a facial expression.
Any deliberate exaggeration, suggestion, or hint that aims to convey a misleading or distorted impression, including presenting facts in a way that leads to misunderstanding, is considered falsehood. This commandment prohibits any effort to harm someone’s reputation through misrepresentation, assuming the worst about them, slander, or spreading gossip. Even deliberately withholding the truth, which may cause harm to others, is a violation of the ninth commandment.