He has the ability to do whatever he wants. The only things He cannot do is be contrary to Himself. He cannot lie. He cannot sin. He is supreme.

Isaiah 46:9-10
“remember the former things of old;
for I am God, and there is no other;
I am God, and there is none like me,
declaring the end from the beginning
and from ancient times things not yet done,
saying, ‘My counsel shall stand,
and I will accomplish all my purpose”