The Flag-Capturing Hero in the Fairy-Tale World

God: "I have a mission to give you: save the world..."

Su Yan: "Yeah, right."

God: "The mission to save the world..."

Su Yan raised his middle finger. "Heh. Yeah, right."

God: "Save the world..."

Su Yan kept snickering. "Yeah, right."

God: "...Then go save the damn world with a hammer!"

"..."

So here's the question:

How do you save the world with a hammer?

Waiting for answers online. Urgent.