Chapter 63:4-5
The Laws of Wronging a Colleague
4. It is forbidden to deceive other people. (This includes creating a false
impression even though one does not cause the other person any financial loss.)
This prohibition applies to deceiving a non-Jew as well. Thus, it is
forbidden to sell to a non-Jew meat from an animal which died naturally, if
the non-Jew presumes that it was ritually slaughtered. Similarly, if the
person sells a colleague a defective article, he must inform him about the
defect. This applies even if the article is priced appropriately to its
defective state. (See Chapter 182, Law 4.)
(There is no prohibition regarding deception when one gives a present [even
though it appears more valuable than it actually is].)
5. A person should not invite a colleague to dinner when he knows that the
colleague will not eat. Similarly, he should not offer him a present which
he knows he will not accept. It is also forbidden to perform any action in
which one's statements do not express his true feelings - e.g., to make it
appear that he honors a colleague when he does not feel that way. Rather
one's statements should always reflect one's true feelings. One should
speak truth and act with upright feelings and a pure heart.
