A god lays his hand in the wolf’s jaws though he knows he will lose it. Tyr embodies the idea that justice demands a sacrifice.
Tyr is one of the oldest gods of the North – originally probably a sky god and chief god, later god of law, the assembly and war. His nature is shown in a single, unforgettable story.
The wolf Fenrir, a child of Loki, grew up and became so huge that the gods feared him. They resolved to bind him. Twice he burst the strongest chains. So the dwarves made a thin, magical ribbon: Gleipnir, woven from impossible things.
Fenrir sensed the trick and would only let himself be bound if a god laid his hand in his jaws as a pledge. Only Tyr was willing. When the wolf realised he could not tear the ribbon, he bit down – and Tyr lost his hand. But the wolf was bound.
Tyr knowingly sacrifices his hand so that order is preserved. Justice here is not comfortable but has a price. On weapons people carved the Tiwaz rune named after him, to ask for victory and a just verdict. His name lives on in Tuesday (from Tyr / Tiw).
You will find the Tiwaz rune and its meaning on its own detail page in the Rune Lexicon.