Theists always rely on the same unconvincing and totally blinkered arguments. They assume everything consistent with texts found in their Holy Book is true, and everything that conflicts with this Holy Book is untrue. They do this because they actually believe their Holy Book is the word of their God.
It really is that simple. As far as theists are concerned, that’s just the way it is. They never bother to substantiate their assertions. They just point to their Holy Book and claim they are right. In reality, they simply define what they think is right, and if you disagree, then by their definition you are wrong. QED.
Atheists run into this brick wall all the time. I use to stand my ground and fight back, but these days, more often than not, I’ll just move on and leave them to their delusions. I don’t even bother to steer them towards my book anymore. There’s no point. The few theists brave enough to read it, pick the book up thinking its rubbish, and then proceed to confirm they were right. Most theists it seems have great difficulty thinking outside of the box. Anything threatening their long-standing status quo is robustly dismissed, and all suggestions that they might be wrong are automatically rejected with the usual “I’m right, therefore you’re wrong” attitude.