Answer
It's important for evangelicals to be familiar with critical approaches to the Pentateuch for a variety of reasons. Many commentaries just assume these critical approaches, and so if you're going to really appreciate a commentary and use it effectively, intelligently, you need to know where the author is coming from. If he's a form critic, diachronic critic of some kind, rhetorical critic, it just helps to understand the perspective of the commentary, evaluate it critically, and use it most efficiently. I find studying critical scholarship helpful even though I disagree with so many of the conclusions because it surfaces the issues for me. If I'm reading a source critic and he is arguing that these two passages contradict in some way, well that's a challenge to me. Because of my presuppositions regarding Scripture, I don't think they contradict. They may there may be a tension, but I need to explain what's going on with those passages. And so I find it helpful. It surfaces issues that I might just have missed if I had used the typical evangelical, conservative, let's-trust-the-Bible-on-everything kind of approach. So, I guess that's kind of a backdoor value to them, but that's why I like to read these guys, and gals, these days.
Answer by Dr. Robert B. Chisholm, Jr.
Dr. Robert B. Chisholm, Jr. is Department Chair and Professor of Old Testament at Dallas Theological Seminary.