To bear false witness means to make a false statement about another person that can harm them, whether that statement is sworn testimony in a courtroom or a damaging lie told in everyday life. The phrase comes from the Ten Commandments, but the conduct it describes is governed today by a web of criminal perjury laws, federal false-statement statutes, and civil defamation rules. Lying under oath in a federal proceeding can land you in prison for up to five years, and a false statement made in casual conversation or online can trigger a lawsuit for money damages.
Where the Phrase Comes From
“You shall not bear false witness against your neighbor” appears in both Exodus 20:16 and Deuteronomy 5:20. Most Protestant traditions number it as the Ninth Commandment; Catholic and Lutheran traditions list it as the Eighth. The numbering differs; the rule is identical.
In ancient Israelite society, oral testimony carried enormous weight. There were no surveillance cameras, no forensic labs, no paper trails for most transactions. If someone accused you of theft or violence, the community’s judgment turned almost entirely on what witnesses said, and a false accusation could cost a person their livelihood, their standing, or in capital cases their life. The commandment’s original scope was legal testimony, but over centuries its reach expanded to cover gossip, rumor, and casual dishonesty about anyone whose life your words could affect.
Bearing False Witness Under Oath: Perjury
The modern legal equivalent of the commandment’s original meaning is perjury. Federal law makes it a crime for anyone who takes an oath before a tribunal, officer, or other authorized person to willfully state something they don’t believe to be true. The false statement has to be “material,” meaning it has to matter to the proceeding. A conviction carries a fine, up to five years in prison, or both.1Office of the Law Revision Counsel. 18 U.S. Code 1621 – Perjury Generally
A separate statute covers false declarations made specifically before a federal court or grand jury, with the same five-year ceiling in most cases.2Office of the Law Revision Counsel. 18 U.S. Code 1623 – False Declarations Before Grand Jury or Court
Materiality is where many perjury cases live or die. Prosecutors must prove not only that you lied under oath, but that the lie was relevant to what was being decided. Courts read the requirement broadly: if the false statement could have influenced the outcome, it generally qualifies.
State perjury laws follow the same basic structure. The exact penalties vary, but perjury is treated as a felony across jurisdictions.
Lying to the Government Without an Oath
You don’t have to be sworn in to commit a federal crime by lying. A separate statute makes it a crime to knowingly make a false or fraudulent statement to any branch of the federal government. This reaches lies on federal applications, false claims to investigators, fraudulent documents submitted to an agency, and the concealment of a material fact during a federal inquiry. The maximum penalty is five years in prison, a fine, or both; for statements involving terrorism, the ceiling rises to eight years.3Office of the Law Revision Counsel. 18 U.S. Code 1001 – Statements or Entries Generally
This is the statute that catches people off guard. Federal agents conducting interviews usually don’t place anyone under oath, but a lie told in that setting is still a federal crime. Plenty of high-profile convictions have turned not on the underlying conduct being investigated, but on false statements made during the investigation itself.
Getting Someone Else to Lie
Bearing false witness isn’t limited to the person speaking the words. Federal law also criminalizes persuading or pressuring someone else to commit perjury, an offense called subornation of perjury. If you procure another person to lie under oath, you face the same ceiling: a fine, up to five years in prison, or both.4Office of the Law Revision Counsel. 18 U.S. Code 1622 – Subornation of Perjury
Coaching a witness to shade the truth, pressuring a business partner to back up a false story in a deposition, or instructing an employee to lie on a government form can all fall within this rule. The person doing the persuading never has to take the stand to be charged.
Bearing False Witness Outside the Courtroom: Defamation
Outside legal proceedings, bearing false witness takes the form of defamation. Spoken falsehoods are slander; written or published ones are libel. Defamation is primarily civil, not criminal: the person harmed sues the person who made the statement and seeks compensation.5Legal Information Institute. Defamation
To win a defamation claim, a plaintiff generally has to prove four things:
- A false statement of fact, not an opinion.
- Publication to at least one person other than the subject.
- Fault on the speaker’s part, at minimum negligence about whether the statement was true.
- Actual harm to reputation, finances, or emotional well-being.
Damages can cover lost income, professional harm, and emotional distress. A handful of states still allow criminal liability for certain defamatory statements, but civil suits do the heavy lifting.5Legal Information Institute. Defamation
When a False-Sounding Statement Isn’t Actionable
Several well-established defenses protect speakers even when a statement sounds damaging.
Truth
If a statement is true, it cannot be defamatory. The U.S. Supreme Court built this principle into First Amendment doctrine in New York Times Co. v. Sullivan in 1964. The statement doesn’t have to be perfect in every detail; courts ask whether the “gist” is substantially true. If it is, the claim fails no matter how much harm the statement caused.6Justia Law. New York Times Co. v. Sullivan, 376 U.S. 254 (1964)
The Public Figure Standard
The same decision set a higher bar for public officials and public figures. Instead of negligence, they must prove “actual malice,” meaning the speaker either knew the statement was false or acted with reckless disregard for whether it was true. The standard is intentionally hard to meet, on the view that public debate needs breathing room.6Justia Law. New York Times Co. v. Sullivan, 376 U.S. 254 (1964)
Opinion
Defamation requires a false statement of fact. Pure opinions are protected. “I think that contractor does terrible work” is opinion. “That contractor used substandard materials on the Johnson project” is a factual claim that can be tested. Courts look at the full context of the statement to decide which side of the line it falls on.
Absolute Privilege Inside Legal Proceedings
Statements made by judges, lawyers, parties, and witnesses in the course of judicial proceedings carry absolute privilege and cannot support a defamation lawsuit, even if false and malicious. The idea is that courts work better when participants can speak without fear of being sued over every unfavorable word.7Legal Information Institute. Absolute Privilege
That creates a split worth understanding. A witness who lies under oath can’t be sued for defamation over that testimony, but can be prosecuted for perjury. Defamation law stands down inside the courtroom; criminal perjury law takes over.
Anti-SLAPP Laws
About 40 states and the District of Columbia have anti-SLAPP laws, which stand for “Strategic Lawsuits Against Public Participation.” These statutes offer a fast-track dismissal for defamation suits filed mainly to silence speech on matters of public concern rather than to remedy real harm. When a court grants an anti-SLAPP motion, the suit is dismissed early and the plaintiff may have to pay the defendant’s attorney fees. These laws come up often with online reviews and social media posts.
What Being Caught Costs You
The statutory penalties aren’t the whole picture. A perjury conviction is a felony on your record, and licensed professionals — attorneys, doctors, accountants, engineers, real estate agents — can face disciplinary proceedings, suspension, or permanent loss of their license after any conviction involving dishonesty. Licensing boards treat crimes of dishonesty as direct evidence of unfitness to practice.
Even without a conviction, a witness caught lying in a deposition or at trial can be held in contempt, and their credibility in any future proceeding is effectively finished. In civil litigation, a party caught lying may face sanctions, adverse inferences (where the court assumes the truth was unfavorable to them), or outright dismissal of their claims.
The ancient commandment captured something that modern law still enforces: dishonesty about other people causes damage that’s hard to undo, and the system responds to it both as a crime, when the lie is sworn or told to the government, and as a civil wrong, when the lie goes out into the world and harms a reputation.