How to argue against this claim

[Esquilax]

Hi All,

So Obviously the Bible and god ways are full of evil deeds, and EVIL agenda
Slaves, murders and much more

Some Religious person would say,
Yeah but think of a child that sees a doctor cutting a man legs to save his life.
So like us the child lack of understanding the big picture.

Please give smart way to explain this comparison

Thanks

The truth is, you don't need to argue against this at all, because this isn't an argument. It's an assertion.

Analyze what's actually being said: It's essentially "pfft, you don't know!" but if I was going to be generous I'd phrase it as "god must have sufficient reasons for it, that we don't know about."

So first of all, if we don't know about it, how can you possibly know that god has sufficient reasons? The first premise is a knowledge claim that the second premise cheerfully states does not exist. It's self refuting, which makes it an assertion; the person making this claim doesn't know that god has a good reason, can't demonstrate that he does, and actually features that ignorance as a key part of the whole thing: why should any of us take it seriously?