What did Jonas learn about the community's rule about lying in The Giver?

Jonas learns that this rule isn't an absolute one.  Early on, he was chastised for saying "I'm starving".  His instructor reminded him that he had never actually starved, nor would he ever starve, so this was an unintentional lie due to lack of language precision.  However, later on, after being selected for his position as receiver of memories, his instructions inform him that he may lie.  This is the first he has ever heard of lying being permissible.

While his first lie involves not telling his dreams to his family, as the rules prohibit the sharing of dreams from the time he was selected, he learns that the Giver may also lie.  This being said, the Giver assures Jonas he has not lied to him at all, which Jonas believes.  Another person who does lie, however, is Jonas' father, who is a nuturer involved with the selection and rejection of infants for induction into the community.  When he releases babies, he tells the family the baby is sent off to "elsewhere"; in fact, he is actually killing them by lethal injection, boxing them up, and sending them down the garbage shute.