Last week we differentiated between two types of falsehood; one is when
lying to someone denies him information that he deserves or causes him
some kind of damage. For example, deliberately deceiving a prospective
customer about the quality of an item. This form of falsehood is forbidden
by the Torah.
The second kind is when the lie is not directly relevant to the other
person, and does not harm him in any way. An example of this is lying
about a specific detail in one’s personal life that is of no concern to
anyone else. This form of falsehood is not forbidden by the Torah, but
the Rabbis forbade it. There are certain circumstances in which it is
permitted to lie in this way. For example, for the sake of maintaining
peace, privacy, or not hurting someone’s feelings.
With regard to the form of falsehood that is prohibited by the Torah there
is one specific circumstance in which one may be permitted to lie; when
another person is trying to trick or lie to you then you may be allowed to
deceive him. This leniency is derived from the story in the Torah
involving Jacob deceiving his father Isaac: Isaac had two sons, Esau and
Jacob, Esau was the elder and was Isaac’s favorite. Isaac believed he was
righteous and therefore wanted to give the main blessing to Esau and not
Jacob. Isaac’s wife, Rebecca, knew that Esau was really an evil man and
had deceived his father into believing that he was righteous. She knew
that there would be a terrible consequences if Esau received the blessing.
Therefore she persuaded her other son, Jacob, to pretend that he was Esau
and thereby deceive Isaac into giving the blessing to him.
The commentaries ask how it was permissible for Jacob to blatantly mislead
Isaac in this way. They explain that Esau himself had spent his whole
life deceiving Isaac, and that it was permissible to resort to falsehood
in order to undermine the deceit that he had perpetrated. Lying to
overcome a liar is not considered a transgression of the Torah’s command
It is very important to note that this leniency only applies to very
specific situations and that it is very easy for one to decide that his
competitor is a deceitful person and therefore it is permissible to use
misleading tactics in order to overcome him. This is generally an invalid
form of reasoning - it is only permissible to used such tactics when it is
very clear that the other person is blatantly acting deceitfully and even
then it is highly advisable to consult with an Orthodox Rabbi without
deciding such matters oneself.