I've been skimming over Augustine and Beckett on Augustine in search of material for the Pascal essay. Here's a paraphrased ponderance for you.
The practice of apologetics (arguing in defense of the faith) must also involve an authentic witness of our lives.
This is because a conversion to Christianity is not simply an intellectual conclusion at the end of a series of irrefutable arguments. It is a new way of being which, "unless you believe you will not understand." (Augustine, City of God, Book IX)
That is, to make the leap from unbelief to belief is not to master Christianity with your mind (although our mind can bring us to the point of wanting to believe). The leap of faith is to enter a new way of existing in relation to God and the world. God becomes incarnate; the world becomes creation.
Using our reason, then, is not an absolute value. It does not answer all questions. From the view of the believer, however, all things take on a new meaning and the questions of the human heart come closer to their answer in God made flesh.
Nisi crediteritis, non intellegetis.
Unless you believe, you will not understand.