WHY DO CHRISTIANS LIE
From all the preceding Bible verses, it would seem that lying would never be acceptable. However, this is not necessarily correct, since there are times that telling the truth would actually facilitate the exercise of evil.
What about Christians who lie?
It often seems that Christian leaders get caught all the time lying or having affairs or doing some other evil thing that contradicts the tenets of Christianity. The perception that this is common is a function of the news media, which loves to report such kinds of behavior. Everyone loves to hate a hypocrite. When famous atheists commit adultery (even on a routine basis) it isn't news at all, since there is no tenet of atheism that one be faithful to his spouse.
Although there are "Christians" who lie, we can't be sure that they are really Christians at all. This is because being a Christian isn't based upon what a person says, but what Jesus says at the judgment. According to Jesus, many who claim to do things in His name will be rejected by Him at the judgment:
"Many will say to Me on that day, 'Lord, Lord, did we not prophesy in Your name, and in Your name cast out demons, and in Your name perform many miracles?' And then I will declare to them, 'I never knew you; DEPART FROM ME, YOU WHO PRACTICE LAWLESSNESS.'" (Matthew 7:22-23)