This is the twenty-second post on Christian ethics in my ongoing series, theology in bullet points. The first unit in this series had to do with God and Creation (book here), and the second unit was on Christology and Atonement.
We are now in the third and final unit: The Holy Spirit and the Church. The first set of posts in this final unit was on the Holy Spirit. The second set was on the Church. The third set was on sacraments. This final section is on Christian ethics.
Truthtelling is almost always the loving thing to do.
1. The previous article focused on the original nature of the commands not to bear false witness or to take the LORD's name in vain. What then of lying and truthtelling in general?
There are more general statements about lying scattered here and there in the Bible. For example, Leviticus 19:11 briefly told the Israelites not to deal falsely or lie to one another. The idea of "dealing falsely" suggests that trustworthiness in the way neighbors interact with each other was probably in view. Proverbs 12:22 says, "Lying lips are an abomination to the Lord, but those who act faithfully are his delight." The context again suggests harmful deception: "Deceit is in the mind of those who plan evil" (Prov. 12:20).
In the New Testament, Satan is called the "father of lies" (John 8:44). Colossians 3:9 tells Christians, "Do not lie to one another, seeing that you have stripped off the old self with its practices." Finally, Revelation 21:8 says that the final destiny of all liars will be "in the lake that burns with fire and sulfur, which is the second death."
2. So what is it about lying that receives such a negative verdict across the Bible? It is because lying is usually either harmful or selfish. In the Old Testament, to lie as a witness was potentially to cause an innocent person to die or suffer. When a person made an oath, he or she made it to assure someone else of something very important. Lying about such an oath, breaking trust, not only dishonored God (in whose name the oath was likely made) but meant that whatever serious action was taken on the basis of the oath would fail.
From a New Testament perspective, lying usually does not fit either with the love of God or of one's neighbor. It does not fit with love of one's neighbor because of the harmful dimension I mentioned above. Lying usually breaks trust, which is a fundamental human value. Trust frees us from worry. Trust means we do not have to expend our energies protecting ourselves or making alternative plans. Trust eliminates uncertainties.
But lies mean that we cannot trust. They mean that we must expend our energies being prepared for alternative situations. If we believe lies, then we may make choices that lead us to harm. We may damage other relationships because we have faulty information. We may buy goods or services that do not work. We may end up looking foolish or shamed.
A person who is known for lying is not trusted. We tend to ignore what they say or even actively assume that they are giving us skewed information. They hurt themselves because people do not fully enter into relationship with them because they cannot be trusted. They find themselves isolated and alone. When they need others to trust them, they are not trusted. 
A person whose word can be trusted is highly valued and honored. Even those who do not believe in Christ will usually respect an honest person.
3. There are various ways to lie, other than an "out and out lie." There is the half-truth, which is partially true but misleads in some key way. There is the "fib," which lies about some trivial matter. One can "act a lie," where one does not speak a lie but one's actions are intended to mislead. In general, any word or act that is intended to deceive or mislead is a form of lying.
By contrast, to unintentionally give misinformation is not a lie. Similarly, to truthfully state your intentions and then fail to reach them is not a lie. As with all ethics, the key is the intention. If one did not intend to lie and gave faulty information, one has not lied. If one intended to be there at 5pm and got stuck in traffic, one has not lied.
A person can also make promises lightly or be half-hearted with truthtelling. They may only half intend to do what they say. They say they will do something, but maybe they will and maybe they won't.
Jesus said to "Let your word be 'Yes, Yes' or 'No, No; anything more than this comes from the evil one" (Matt. 5:37). Being reliable in what you say is a core Christian value, and it is the loving thing to do. Even if a Christian lives in a culture where lying is considered somewhat acceptable, a Christian will stand out as different, as a person of truth.
4. Is there ever a circumstance where deception is the right thing to do? That is to say, is it ever right to lie? Most biblical commands are on the level of universal values, but with exceptions. Although the Bible strongly values truth-telling, there may be highly unusual circumstances where deception is appropriate.
The best known example is of course Rahab in Joshua, who lies to the people of Jericho to protect the Israelite spies. This example falls under the category of war and saving life. The Bible never condemns her lie. Rather, she is consistently affirmed throughout Scripture as a hero of faith. Her lie is never specifically affirmed, but it seems to be implicitly affirmed.
But notice that her lie served to protect life. Notice that her lie served to protect God's people. From one perspective, her lie was not loving toward the people of Jericho. But from another, her lie was loving toward the people of Israel in a time of war. When Corrie Ten Boom's family was hiding Jews, it would have been appropriate to lie to the Nazis because of the higher value of saving life.
Personal conscience and strong discernment, as well as culture may come into play with various situations. There are times when a person means another harm and giving them information can become a tool of harm. The full truth, in such circumstances, becomes harmful and unloving, in effect. The loving thing to do is to prevent such intenders of harm from getting information. Misleading may be the right thing to do.
The truth can be hurtful in trivial personal matters. A spouse can use truth as a weapon in such cases. Being less than forthright, on the other hand, can be the loving thing to do. "How do I look?"
There are times when someone has no business to certain information but you are faced with an outright question. To say, "None of your business" may in itself be an answer. Jesus' brothers tell him in John 7:3 to go to the Feast of Tabernacles. But it is none of their business. He tells them he is not going to the feast, and then goes up anyway secretly (John 7:8-10). 
It is probably a matter of conscience as to what one does in such situations. One would not be deceiving in an unloving or selfish way. The intention is not to harm. One might actually be deceiving to protect confidentiality or to protect an important process where information should not get out. Leaders often have to guard information carefully and the line between deception and controlling information can get blurry.
5. Some will always try to emphasize the exceptions to justify their actions. God is not fooled. God knows those whose hearts are disposed to be truthful and loving with the truth. And God knows those whose predisposition is to deceive or to justify lying for the wrong purposes.
Most lies serve selfish purposes. We lie to protect ourselves from guilt or consequences. We lie to make ourselves seem better than we are. We cheat on a test, which is a form of lying, so that our grade does not tell how little we really know. We hide our failures with lies. We hide our sins with lies. But God is not fooled.
Truthtelling is almost always the loving thing to do. There are exceptions when deception is the loving thing to do, but it is the exception. A person after God's own heart is a person of truth and clarity. By contrast, lying is usually either selfish or hateful, neither of which has any place in the kingdom of God.
Next Sunday: ET23: Thou shalt not covet.
 Thus the story of the boy who cried, "Wolf!"
 This story is only told in John and so may be told more in John's language than Jesus' own.