The Hand in the Wolf's Mouth

The one story everybody knows about him is told in the Prose Edda. The gods want Fenrir bound and dress the binding as a test of strength; the wolf, who is not stupid, agrees to the third fetter only if one of them will lay a hand in his mouth as surety. The account says the others hesitate and Tyr does it. When the ribbon holds and the wolf cannot break free, the hand goes. He is the only one in the scene who offered, and the text treats the loss as the price of a pledge that everybody else present intended to break.