Tyler's father gently teaches him to "Stop telling lies. Tell each other the truth" (Ephesians 4:25). Rhyme and repetition help kids memorize this verse.
This is a Christian book that really helps with lying. It gives examples of common lies that children tell (stealing a cookie and saying she didnt, etc). I often reference this with Taylor and she immediately confesses that she is not telling the truth. It is a simple and easy read. It held my classes attention and they loved it.