Gandalf and the Goblins - Chapter 17

Gandalf has spies everywhere, and he knows the goblins are bringing an army also. But he doesn't tell Bilbo about it. So next day, Bard and the elven king, and it says an old man in a cloak,. Of course it's Gandalf, but they he's he's hiding himself. They come back to Thorin again back to the wall, right to negotiate. And then he says, how did you get it? Thorin yells at them. Then Bilbo kind of, and a little voice says, I gave it to them. I did it, right? He grabs Bilbo and he shakes him. And he's going to throw him off