The first question to ask when looking at the question of 'Can God lie?' is a look at which God or god this is being asked of. Many
old religions have a
trickster god as part of the
pantheon. Such a being as
Loki, the
Coyote, or
Hermes has it as part of the very nature of the being to
lie,
cheat, and be a general trickster. In these stories, it is not only the trickster gods that lie or deceive, but a fair portion of the pantheon too (as Hera asks Zeus "Honey, have you impregnated any more young maidens today?").
This changes when the pantheon is reduced to one supreme being as it is with the Jewish, Islamic, and Christian branch of religion as this question implies, one must look at the nature of the supreme being and the attributes that are ascribed to it.
The JIC God has three key components as part of His being:
While there are debates as to if any or all of these are
contradictory in nature, the question of omnibenevolance and omnipotence comes into play with the question of "Can God lie?".
To an extent, the question of "Can God lie?" pits the ability of being able to lie (mandated by omnipotence) with His omnibenevloant nature prohibiting Him from doing so. This is similar to the question of "Can God make a square circle?" or "Can God make a rock that He can't lift?"
Descartes works from this in several of his arguments for the existence of material objects (the world) - that God exists, and that God is not a deceiver.
- God is no deceiver
- He created me and gave me reason which tells me that my ideas come from external corporeal things.
- If they do not come from external objects, then God must be a deceiver. But this is an absurdity
- Therefore - Material objects exist
The classic definition of omnibenevolence with regard to God is that God is perfectly good. There are a fair number of examples in the Old Testament where one may reasonably call into question the aspect of omnibenevolence (casting out of Eden, the flood, Tower of Babel to name a few). Assume for the sake of argument that God is omnibenevolant - if he isn't, then there is less of an argument for that God is not a deceiver and the very computer that you sit in front of reading this will disappear in a puff of logic as you find yourself to be awaken as a brain in a vat.
If God is perfectly good, then He will not lie. This can be reasonably upheld given the works available (I can't think of any instances in the Bible where God didn't uphold His side of a deal - though this can easily be countered with it just may not be recorded). Just as a vegetarian has the free will choice of to exercise the power of eating meat or not, God has the free will choice of exercising the power of deceiving or not. The outcome of this should be fairly apparent to even someone without omniscience.
Yes, God can lie and deceive us. However, doing so is not in His nature. The ability to do so exists and is not in conflict with omnipotence. Nor does this refusal of deception contradict His free will. One may accept on faith (the same faith that presupposes the existence of God) that God will not lie or deceive us.