Truth and God
"What is truth? Truth is something so noble that if God could turn aside from it, I could keep to the truth and let God go."
-- Meister Eckhart1
"God," as God is typically understood, poses something of an obstacle for a lot of people. The most enlightened saints and doctors of the church have emphasised the ineffability of God, but that hasn't stopped people from saying a great deal about God. The result is a notion that many of us can't subscribe to. Still, we can't avoid having an idea, even if we understand that any idea will be inadequate.
I find it helpful to equate God with "Truth." If it is difficult to know precisely what "fidelity to God" entails, the same cannot be said of "fidelity to the truth." We all know what it means to be "truthful," and we know what it means to be "untruthful," and if we are honest -- truthful -- with ourselves, we know when we are being one and when we're being the other.
Truth and Religion
I imagine that most people would say that they would rather believe the truth than their current religious beliefs, if their beliefs happened to be mistaken. At the same time, it seems to me that a lot of people act as if the opposite was true. They shield themselves from other viewpoints, presumably fearful that they will "lose their faith," that they will come to believe something other than what they believe now.
But it seems to me that if one approaches alternative viewpoints with fidelity to the transcendental precepts -- be attentive; be intelligent; be reasonable; be responsible -- one cannot fall into error. It is possible that one will discover that the grounds for one's beliefs are not as strong as one had thought. But isn't it better to know that you don't know something, than to think that you do, when you don't? That would be more truthful!
In any case, one cannot follow the transcendental precepts and fall away from truth into error.
Perhaps people who fear alternative perspectives do not trust their ability to be attentive, or intelligent, or reasonable, or responsible. And, indeed, there are people who are inattentive, or unintelligent, or unreasonable, or irresponsible, or any combination of these. But if they are aware of this, why do they trust their own judgment that what they believe currently is correct?2
Or, perhaps people are afraid that if they question their beliefs, they will discover that their beliefs are not true. There is something profoundly irrational about this -- after all, if one discovers that one's beliefs are mistaken, one is moving closer to truth -- but I suspect this is a common fear. People have been told that their salvation depends on holding these beliefs. Of course, if those beliefs are untrue, can it be the case that salvation depends on believing them? What kind of God would require that people hold false beliefs?3
It seems to me that it is rather unwise to be protective about what you believe. If what you believe is untrue, not thinking about it means remaining in error. If what you believe is true, it can withstand intellectual scrutiny. There's nothing fragile about the truth.
 O'Neal, Meister Eckhart, 3.
 I suppose they would argue that they are not trusting their own judgment, they are trusting the judgment of, say, the leaders of the church, or some other authority. But to choose to trust someone else's judgment is itself to make a judgment. They're is no getting around that.
 One might question what kind of God requires people to hold any beliefs that are as incredible as many Christians believe, but this is a separate issue.