I recently was flipping through a fairly interesting book on human psychology in a book store which made many interesting points. Of course one section was interesting and I thought I'd object to the book without naming it.
It basically contained a few sample dialogues of hypothetical situations in which people were asked to give their opinion on a topic and then explain why their rational.
A few of the people said "because it is wrong" as an answer and they were pressed for a rational. The specific issues are irrelevant to my point. Often Christians today are being pressed by non believers to give reasons why things are wrong past "God says it is."
It is certainly good if the Christian can give an apologetic for his beliefs, but ultimately we see many Christians discouraged because they don't have an answer past "God said." Ultimately if God says it is then we can feel confident in our position.
You see if it is God who said it the argument is over if we truly understand the situation. An apologetic is useful to have of course, but the apologetic or the rational is far less important than the point that it is God's will not ours that matters.
Often as Christians we get pressed for reasons we don't have at the moment. It is often very unfair the way debates go. You might press an atheist for a reason for something and they simply say you should go read such and such a scientist and that scientist has the answer.
Of course if I tell them you should go read this or that theologian and I know they can answer your question, then the atheist will become quite upset. You see we are often unfairly held to the standard of master theologian/apologist in debate by the atheist who refuses to be held to the level of professional physicist/astronomer.
Needless to say the point is often in debate or discussion we can feel discouraged. And we need not feel so. The world often holds the church to standards of evidence it does not hold itself to.