Since we are talking about breakable things, we are in the physical realm and time is involved.
Suppose, at time t = (5th July 2008, 12pm)
A person asks God, “Create an unbreakable shield.”
God says, “Fine. Here’s a shield. There’s nothing (
material) existing in the world **at this point of time **that can break this shield. It is impossible to break it by any
physical means. But since, I’m a
spiritual being, I can break it if I want to, with my spiritual power. For there is nothing in this spiritual realm that I cannot “break”. **I am the only one who is “unbreakable”

**”
Person: “That’s perfectly fine with me. I don’t want it to be broken by any physical means **now existing **or
which you might create in the future.”
Now, the unbreakable shield is in existence.
Time passes. At time t = (10th July 2008, 12pm)
The person asks God: “God,
create a sword that can pierce through anything.”
God: “
I cannot do it! 5 days ago, I created a shield that no physical force can break.”
Person: “Hey, **but I thought that you could do anything **because you are God! If you can’t do everything, then
you can’t be God.”
God: “
I can indeed do everything, as long as I don’t contradict myself. I am the
TRUTH. There is nothing that is false in me. If I do something that contradicts myself, I cannot be the TRUTH. I** can never do anything that contradicts myself**, I never do anything that is false.”