First off, your honor, the Bible is a book of proverbs and mythology. I can't believe any reasonable person thinks some god is going to swoop down from his cloud and strike me dead if I do lie.
Both Nixon and Bush swore on a Bible they'd defend the Constitution of the United States and neither of them did. I don't recall any divine retribution in their cases. How many people are currently in prison for perjury? How many have been charged? Has any god taken action against them?
My testimony is the truth only as far as I know it. I don't claim to have an objective viewpoint that allows me to observe reality free of the bias of my experiences and mental abilities. Maybe I'm not even aware of the truth of this matter but only think I am. I can't say that everything I give testimony to is going to be the whole truth and nothing but the truth. I'm only human. I get confused, my memory isn't perfect, I'm a bit intimidated just being here, treated like some authority on the facts when I know I'm not. So I can only promise on my word (and since none of you really know me, how comforting is that?) that I'll relate what I think I remember. Perhaps I'll lie without meaning to. I'm not perfect. It's quite possible that what I remember regarding this case is so far from reality that it will only detract from the court's desire to uncover what really happened here.
You know, your honor, perhaps it's best that I just don't testify at all. I don't believe in your god, so the only fear you can put in my mind is the fear of going to jail for perjury, and with the economy the way it is at least there I'd get some sleep and regular meals. I might even have the opportunity to have sexual relations again. It's been quite a while, your honor.
Further, I have no idea if what I think I remember is the truth or even remotely related to the truth. I'd sure hate for anyone to take my testimony for the whole truth, whatever that is. At best it would be my imperfect recollection of events that may or may not have any relation to this case. It would be unfair and sadden me to have someone convicted based on my personal perception of reality.
My statement is all I can really be sure of in this matter. Can I go now, your honor?