The question of whether God's truth is divinely hidden from some is a vital one in Christian doctrine. With their great emphasis on truth or knowledge as the route to God's approval, the mechanism by which truth is disseminated and effectively communicated is of obvious interest. Christian Orthodoxy seemingly recognizes a combined effort between God or the Holy Spirit and some human intermediary, like the preacher. Man plants and waters but God grants the increase to put it in biblical terms.
In introducing divine influence into the evangelism process, a number of side issues arise. For instance what determines the effectiveness of the evangelistic effort if God is involved? Why, in fact, would evangelism work for some and not for others if ultimately God finalizes the deal?
The Calvinists supply one possible answer: God has arbitrarily chosen a few to be saved and the Holy Spirit makes that happen for those and not for the "unchosen" ones. Pre-destination addresses the question but not in a way that many find palatable.
More generally, Christians seem to conclude that some folks are just hard hearted and resist the working of God. This allows God to work equally hard to save everyone and assigns the blame for failure on the individual hearer. This is concept maintains the idea of personal responsibility and eliminates the need to exonerate God in His role.
The above conclusion simply begs another question. Why are some people receptive to the church's message and some are not? All are supposed to be unavoidably tainted by sin. All have the same need, but some recognize the need and respond as taught, and others do not. What differentiates the receptive heart from the hardened one? Is it the love of sinning that exists in a greater measure in the one than the other? Does the inherited depravity of Adam affect some more dramatically than others? Is rejection of the church's message a willful decision on the individual's part or is it the result of other factors?
Within the context of this discussion we might consider what the Bible says about God's specific action in causing unbelief in men. In Exodus we read about God hardening Pharaoh's heart, apparently causing him to reject God's demand as given by Moses. This incident seems to reinforce the idea that God influences what men believe and accept, but in a sense very different from that assumed in many evangelical circles. Even more dramatic is the account of Jesus in John 12:39 when he says that God prevented belief in the Jews in accordance with the prophecy of Isaiah.
To the extent that God causes unbelief then individual men cannot be reasonably responsible for their lack of faith. If God caused unbelief, that unbelief served His purpose, clearly. In both examples cited, that purpose is given. Unbelief was exercised to bring about glorification. God was glorified in Pharaoh's case because He repeated His dominance over