Today's quote comes from none other than Christian apologist extraordinaire William Lane Craig. In his apologetic handbook Reasonable Faith he writes about the "legitimate" use of reason:
The magisterial use of reason occurs when reason stands over and above the gospel like a magistrate and judges it on the basis of argument and evidence. The ministerial use of reason occurs when reason submits to and serves the gospel. In light of the Spirit's witness, only the ministerial use of reason is legitimate. Philosophy is rightly the handmaid of theology. Reason is a tool to help us better understand and defend our faith; as Anselm put it, ours is a faith that seeks understanding. A person who knows that Christianity is true on the basis of the witness of the Spirit may also have a sound apologetic which reinforces or confirms for him the Spirit's witness, but it does not serve as the basis of his belief. 
Let's briefly examine this. According to Craig, the only legitimate use of reason is in its ministerial sense of submitting to and serving the gospel. In other words, according to Craig, reason, argument, and evidence cannot exist outside of the gospel to judge the gospel on its veracity or to contradict it. Instead, reason, argument, and evidence only exist to serve the gospel's presupposed truth. The gospel basically determines what's reasonable. The basis of Christian belief according to Craig is not reason, argument, and evidence, it's the witness of the Spirit. That is, it's a warm fuzzy feeling one gets when they read the Bible, or "talk" or pray to Jesus and Yahweh. This is a horrible way to infer ontology, as I've written, and it goes to show you that all of Craig's evidentialist ramblings are really just a post hoc rationalization.
 Craig, William Lane (2008-07-23). Reasonable Faith: Christian Truth and Apologetics (Kindle Location 686). Good News Publishers/Crossway Books. Kindle Edition. (Emphasis mine)