The God paradox is an idea in philosophy. This idea is explained here:

If God is able to do anything, may this mean He is able to make a mountain heavier than He is able to lift?

This is a paradox because:

• If God is able to make a mountain heavier than He is able to lift, then there may be something He is not able to do: He is not able to lift that mountain. Yes and no
• If God is not able to make such a mountain, then there is something He is not able to do: He is not able to make that mountain.

If either outcome were considered true, then it is argued that God Almighty is actually not almighty.