Simple mistakes are not lies. Jokes are not lies. No one is morally bound to tell the enemy the truth. The Biblical tradition is absolutely against lying. One never errs more safely than when one errs by too much loving the truth.
Some lies are understandable, some are worse than others, but all lies are wrong.
A. God is truth. B. Satan is the father of lies. We lie to get revenge. Lying is serious business. A. Christians must attack it.