The angel Gabriel, in speaking to Mary commending her belief said, “For nothing will be impossible with God.” (Luke 1:37) The literal translation of the word for nothing is “not any word”.
We frivolously say that “God can do what ever he wants.” Maybe so, but he doesn’t want to do just any thing, and will only do what is good. God’s power is not the fairytale idea of using power to do anything.
God’s word is true, and not any word of his is impossible for him to do--though it may be impossible for us to do or for us to imagine him doing it.
He can and will always fulfill his word. If he says he will do something, he is more than able to bring it about; our part is to believe what he has told us. He doesn't ask us to have a fairytale belief. He asks us to believe him.
In Luke 1:45