Exodus 20:16 (and Deuteronomy 5:20) say, "You shall not give false testimony against your neighbor." That's a bit more specific type of lie than a general "Thou Shalt Not Lie" (or, in modern wording, "You should not lie"). What this is saying is that making false claims against others is expressly condemned and forbidden by Scripture. Giving false testimony sounds like this refers to legal situations, but is it restricted to that context, or is it more broad?
Let's look at some other passages that address this issue:
- Ex. 23:1: "You shall not spread a false report. You shall not join hands with the wicked to act as a malicious witness."
- Deut. 19:18-19: "If the witness is a false witness, having testified falsely against another, then you shall do to the false witness just as the false witness had meant to do to the other. So you shall purge the evil from your midst."
- Job 15:35: "They conceive mischief and bring forth evil and their heart prepares deceit."
- Psalm 10:2-3,7: "2 In arrogance...the wicked boast of the desires of their heart, those greedy for gain curse and renounce the Lord. Their mouths are filled with cursing and deceit and oppression; under their tongues are mischief and iniquity."
- Psalm 34:13: "Keep your tongue from evil, and your lips from speaking deceit."
- Psalm 36:1-4: "Transgression speaks to the wicked deep in their hearts; there is no fear of God before their eyes. For they flatter themselves in their own eyes that their iniquity cannot be found out and hated. The words of their mouths are mischief and deceit; they have ceased to act wisely and do good. They plot mischief while on their beds; they are set on a way that is not good; they do not reject evil."
- Prov. 12:17: "Whoever speaks the truth gives honest evidence, but a false witness speaks deceitfully."
- Prov. 14:5: "A faithful witness does not lie, but a false witness breathes out lies."
- Prov. 17:4: "An evildoer listens to wicked lips; and a liar gives heed to a mischievous tongue."
- Prov. 19:5: "A false witness will not go unpunished, and a liar will not escape."
- Prov. 19:9: "A false witness will not go unpunished, and the liar will perish."
- Prov. 19:22: "What is desirable in a person is loyalty, and it is better to be poor than a liar."
- Prov. 21:28: "A false witness will perish, but a good listener will testify successfully."
- Prov. 25:18: "Like a war club, a sword, or a sharp arrow is one who bears false witness against a neighbor."
- Mt 15:19: "For out of the heart come evil intentions, murder, adultery, fornication, theft, false witness, slander."
- Jn 8:44: "You are from your father the devil, and you choose to do your father's desires. He was a murderer from the beginning and does not stand in the truth, because there is no truth in him. When he lies, he speaks according to his own nature, for he is a liar and the father of lies."
It also makes clear that Satan is "the Father of Lies"...which implies that all such lying is "of Satan" (evil!).
So, is there any kind of lying that is morally/ethically acceptable for Christians? For example, is it acceptable to tell "white lies", if the intent is to save someone's feelings from being hurt unnecessarily? This is a difficult question. As you can see, the "types" of lying that Scripture addresses are, far and away, related to spreading false information about others. However, many passages also warn against general deceit, though again in those cases, there is almost always an "evil motivation" attached. What happens if the motivation is good (not hurting someone)?
Then we get into discussion of ethics. Dietrich Bonhoeffer, a pastor in Germany at the time of Hitler's Third Reich. Bonhoeffer had an opportunity to participate in a plot to assassinate Hitler. He struggled greatly with the decision to participate or not. In the process, he outlined three main questions that must be asked when identifying the ethical dynamics of a given decision/situation/etc:
- Is the motivation good or evil?
- Is the act itself good or evil?
- Is the outcome good or evil?
- Is the motivation good or evil? Good - he wanted to save the lives of thousands (tens of thousands) of Jews.
- Is the act itself good or evil? Evil - murder is expressly prohibited in Scripture, and it violates the sanctity of life.
- Is the outcome good or evil? Both. It's evil in that Hitler will be dead (murdered), and good in that many lives will be saved.
So, applying these questions to the issue of lying, we have to consider the motivation, the act, and the outcome. Scripture seems to say more about the motivation and the outcome than the act itself. The question is whether the act of lying is always "evil" itself. While there is no clear indication of such in Scripture, many passages seem to point to this possibility. I won't attempt to answer this, as I believe that each person must decide for him/herself, with prayer and in light of Scripture.
What is clear is that spreading falsehoods about another person is always condemned and forbidden by Scripture. Doing so violates all three of Bonhoeffer's ethical questions: the motive is evil (to spread lies about someone), the act is evil (lying about someone), and the outcome is evil (lies are spread about someone). And Scripture outlines the penalty for doing such, and it is clear and it is severe: "But as for the cowardly, the faithless, the polluted, the murderers, the fornicators, the sorcerers, the idolaters, and all liars, their place will be in the lake that burns with fire and sulfur, which is the second death." (Rev. 21:8). Be warned!