I take what you receive and surrender it all by waving my flag.What am I?

A young man walks through the forest. He comes to a bridge. In front of the bridge is a large man carrying an axe. The man says, “If you want to cross this bridge, you must tell me a statement. If I think the statement is true, you will be strangled to death. If I say the statement is false, your head will be chopped off.” A few minutes later, the young man walked over the bridge, while the larger man stood pondering. What was the statement the young man had given?