1. All truth is God's truth.
Assuming that everything God thinks is true, then it is a tautology to say that "All truth is God's truth." If something is true, then it is obviously what God believes.
2. Most of the time, believing the truth does not require irrational faith.
This one is more debatable. Some would disagree. Certainly the evidence doesn't always point to the truth. Also, I'm not suggesting that the truth is always understood precisely or literally. I'm simply saying that it seems dubious to suggest that God has, in most cases, rigged the world to look like the false rather than the true.
3. Therefore, the more objective we are, the closer we are likely to come to God's thoughts.
And this includes the more objective we are about the Bible. In theory, objectivity about the world shouldn't lead in a different direction than objectivity about the Bible, and vice versa.
All truth is God's truth.