Let's give some rough, basic definitions:
1. Logical Contradiction = state something which is untrue or invalid (often accidental)
2. Lie = intentionally state something which is untrue
3. Bear False Witness = intentionally state something which is untrue ABOUT SOMEONE
God can do NONE of these.
He cannot state an untruth, either intentionally or accidentally.
Man can do all of these:
and they inherently contain varying degrees of moral failure depending on the INTENT.
Priorities of Moral Duty
1. We all know some things are worse than other things; we all have a sense of this.
(Telling a white lie about your wife's cooking isn't as bad as torturing a child.)
2. All sin separates us from God equally, nonetheless, we all know some things are intrinsically worse (MORE HARMFUL) than other things.
3. We can refer to this in different ways, but some would call it our Priority of Moral Duties.
4. Sometimes a lesser duty, like being absolutely truthful about a small matter, is simply outweighed by a higher duty, like saving a life.
5. It is a lesser duty to be completely truthful to a soldier representing the wicked city of Jericho, than to save the life of two Israelites.
Why does God never lie to prioritize his moral duties?
1. Technically, God doesn't have moral duties exactly, but rather all morals of right and wrong flow out of his nature... they are part of his being, not external rules he must follow.
2. It is impossible for God to tell an untruth: it is actually something he cannot do because it is outside of his very nature, just as a fish cannot fly, and a man cannot breathe underwater.
3. God, if he should need to change anything, never needs to LIE in order to do so; God has all power. God can change anything, at any time, without the need to lie.
Humans lie to achieve different outcomes because we have no POWER to change the circumstances.
God however has ALL POWER to change anything he wishes to change.
