According to deontological ethics (Kant), lying would violate a duty we uphold by being human. To be morally correct and truthful to oneself and others. The "duty" is to consider the facts. Looking at the consequences that it may bring is not an option. Even if the lie we tell could harm someone, it would be morally incorrect not to.
Now, utilitarianism (Mill), is the opposite. This ethical view wants the consequences to be throughly thought about. If something grand is going to occur, then the lie may be worth something. When I say grand, I don't mean for the person who is telling the lie. I am not saying go ahead and lie your way around and and up getting a pony. What this means is that the lie is justifiable if it can alter or impact (or save) a persons life in a positive way.
Never lying, or only lying to save a person from death would be a difficult task for many. Little lies are told daily. Is teaching your child to believe in Santa Clause a lie? What about the Easter Bunny? Tooth Fairy? "Does this dress make me look fat...?" What would you say?
So...Who is right? As a Christian, I should know wrong from right. But do I? I have heard many stories where someone does an unmoral act because God told them to do so. Would they have done this unmoral act otherwise? Who knows.
THINKING God told us to do something doesn't ALWAYS justify doing it...