Politicians invoke God and the Bible both because it works, and in cases like that of Governor Sanford who compared himself to King David, because it nourishes their outsized egos — situating their personal dramas within a cosmically significant narrative. It works, because whether the politicians themselves are truly religious or not, we Americans are true believers.
We may like church and synagogue less and less, as recent polling suggests, but our faith in God and love of both biblical language and stories endures. And why not? They really are some of the greatest stories ever told, regardless of what we may think about their status as divinely revealed literature.
Ultimately, the use of such language tells us more about ourselves than it does about the misbehaving politicos. The passage of time is the only way to tell if they are sincere or simply pandering because we never fully know what’s going on inside of another person. In fact, how often do we really know what’s going on inside ourselves?

We make decisions all the time about each other’s words of remorse and acts of contrition, but until someone finds themselves in the same position once again, there is no way to know the full meaning of their repentance. Even when we commit the same transgression again, it doesn’t necessarily mean that our previous apology was insincere. It might simply mean that we couldn’t deliver as we hoped that we would when we confessed our past misdeeds. This is not proof of hypocrisy. It could just as easily indicate that our moral/ethical reach exceeds our grasp.
While genuine understanding of the complex dynamics between remorse, apology and repentance is no excuse for bad behavior, it is a reason to judge each other, and even our elected officials, with both a commitment to justice, and a measure of mercy. Since the Bible celebrates both of those values, perhaps it is we who should invoke the Bible even more than the politicians when it comes to matters of public misdeeds and the proper response to them.