מדבר שקר תרחק
Among the various laws mentioned in פרשת משפטים, is the simple command, מדבר שקר תרחק, that we are to stay away from a false matter.
This is the source from which we learn the importance of being truthful in all matters. Not only are we not allowed to tell a lie, but we are also not allowed to even tell a “white” lie.
Rav Dovid Grossman of Migdal Or, quoted a humorous Gemara that told the story of a man married to a very contrary woman. Whenever he asked for something, she consistently gave him the opposite of what he asked.
Rather than argue with his wife, the husband began “asking” for the opposite of what he wanted, so that he ended up with what he really wanted in the first place!
For this, he was reprimanded, because he allowed himself to act in a deceitful manner. Such behavior on the husband’s part, also fell under the category of מדבר שקר תרחק.