As long as I'm on the topic, let's discuss some complications about truth and falsehood. Biblical prohibitions usually deal with typical or commonplace situations. Some Biblical prohibitions involve moral absolutes, but others concern what's generally wrong. They don't attempt to address exceptional situations. Let's take two cases:
i) It's conventional to distinguish between intentional and unintentional falsehoods. But we can flip that around by distinguishing between intentional and unintentional truths. It's possible to unintentionally make a true statement that you intend to be a false statement. For instance:
In Jean-Paul Sartre’s short-story, The Wall, set during the Spanish Civil War, Pablo Ibbieta, a prisoner sentenced to be executed by the Fascists, is interrogated by his guards as to the whereabouts of his comrade Ramon Gris. Mistakenly believing Gris to be hiding with his cousins, he makes the untruthful statement to them that “Gris is hiding in the cemetery” (with the intention that they believe this statement to be true). As it happens, Gris is hiding in the cemetery, and the statement is true. Gris is arrested at the cemetery, and Ibbieta is released (Sartre 1937; cf. Siegler 1966: 130).
What's the moral status of that statement? Do we evaluate the morality of the statement by its veracity or the intention of the speaker?
ii) Suppose I go hiking with some classmates. One of my classmates harbors an irrational paranoia about me. He thinks I'm untrustworthy. And he thinks I'm out to get him.
Suppose I detect a rattlesnake camouflaged in the grassy trail just ahead of my suspicious classmate. I want to warn him to detour around the snake. He's oblivious to his mortal peril. If he keeps walking in that direction, he will be bitten.
But if I tell him the truth, he won't believe me. Therefore, I use reverse psychology. I lie to him about the actual location of the snake. I anticipate that if I tell him to go left, he will go right. My lie saves his life.
In this situation, he will mistake my falsehood for a truth, or mistake my truth for a falsehood. A true statement would be deceptive to him.
iii) I could resolve the moral dilemma (if that's what it is) by simply withholding the lifesaving information at my disposal. I say nothing and let him step on the snake–with predictable consequences. But is that where my duty lies?
Although this example is fanciful, there are real-life counterparts when dealing with someone senile, mentally ill, high on drugs, or developmentally disabled, where it may be necessary to trick them for their own good.