We will all make bad arguments at some point. What we do at that stage is very important. Do we stand corrected, or do we dig in our heels out of pride? One bad argument can undermine ten good ones, so it is important for us to be correctable. Not just for our own intellectual honesty, but for our witness as Christians.
As I emphasize when teaching how and why to read Bible verses in context, I have made many mistakes over the years. When I realized I had misunderstood Philippians 4:13 or Jeremiah 29:11, for example, I had a choice. I could keep using the wrong interpretations of these verses, or I could change and use the right ones.
An atheism site had a somewhat useful flowchart about rational debating. (Although they conflated debating and discussion — one can be so thoroughly versed on a topic that they can’t reasonable envision something would change his mind and still debate or discuss something).
Interestingly, while they obviously meant this to imply that Christians don’t follow these rules — and I concede that many do not — I have found atheists to break many of these repeatedly. That is especially true on item 2 about moving on to new arguments once you’ve been shown to have used an inaccurate data point. You can refute their arguments in detail and they just move to the next item in their Big Book O’ Atheist Sound Bites. That’s when you know it is pearl holding / dust shaking time.
I also find that they think they don’t need to offer evidence. They just point to the views of their monopolistic leaders and assume that is adequate. Science has been wrong for hundreds or even thousands of years at a stretch, so just because their dear leaders insist something is true doesn’t mean the facts support them.
I find this with false or “saved and confused” Christians as well. For example, no matter how many times you point out how fallacious it is to say, “Jesus never said anything about homosexual behavior / abortion,” they still repeat that tired sound bite, along with many other pro-gay theology arguments. It is a bad sign when people can’t be corrected.
It is a good thing to change your views when confronted with valid reasons to do so. People often stereotype Christians as being close minded, but to be a Christian means that at some point in time one had to admit he was completely wrong about God and the universe and then changed his mind. I wasn’t feeling unpopular enough as a mere Christian, so after years of investigation I switched to Reformed theology. We won’t debate that on this thread and my switch doesn’t make me right, I just point it out to note that I had every reason to stay on the other side but was ultimately persuaded to change because I kept an open mind.
So don’t let your pride get in the way of rational discussions and defending the faith! If you get stumped, don’t say something false. Just say I don’t know, but I’ll find out, then go do some research and get back to the person. In the mean time, feel free to shift the discussion back to what you do know — namely that Jesus lived, died and rose again and saved your soul — and encourage them to read the Bible. Then let God’s word do what He promised it would.