Norse Mythology: The Binding of Fenrir
Loki, the trickster figure of Norse mythology, may have began as a friend and ally of the Aesir (the gods of Norse myth, who made their home in Asgard) - but, later stories portrayed him as increasingly malevolent. It was Loki's machinations, both direct and indirect, which ultimately served to bring about Ragnarok - the end of the world, according to Norse myth.
Loki had, for example, fathered three monstrous children with the giant, Angrboda - each of whom was destined to play a key role in the downfall of the Aesir. These children were the great serpent Jormungand, the half dead and half alive Hel, and the great and terrible wolf Fenrir. As you might expect, each of these monstrous children was a source of great concern to the Aesir - so, it was decided that action need to be taken to keep each of them under control.
Jormungand was cast into the sea by Odin - where the great serpent was free to grow to such a size that it eventually came to completely encircle Midgard. Hel was condemned to Niflheim, where she came to oversee the souls of those deceased deemed not to be worthy of a place in either Odin's realm of Valhalla, or Freyja's realm of Folkvangr.
Of the three, though, it was the great wolf Fenrir who most concerned the Aesir. It was, after all, Fenrir who was destined to slay Odin, himself, during the great final battle. Believing that the young wolf-pup could not be allowed to grow free and unchecked, the Aesir made the decision to bring Fenrir to Asgard - where they intended to raise him, themselves.
Of all of the Aesir, though, only Tyr had the courage to actually approach Fenrir - so, it fell to him to feed and care for the great wolf. Tyr performed this task diligently - as could be expected of one typically considered to be the most honourable off all the Norse gods.
As time passed, though, the Aesir found that the great wolf continued to grow - eventually reaching such an impossible size that even the brave and stalwart Tyr must have felt some fear in Fenrir's presence. Realising that they would never be able to control the great wolf, and fearing that they might not be able to defeat him when he inevitably turned on them, the Aesir came to the conclusion that Fenrir would need to be restrained.
The gods of Asgard worked quickly to find the strongest fetter they could, a heavy iron thing called Laeding - and, approaching the great wolf, they dared Fenrir to test his strength against it. Their plan was a simple one, to trick the great wolf into allowing them to bind him, then to leave him restrained when he proved unable to free himself. Upon taking up the Aesir's challenge and allowing himself to be bound, though, Fenrir shattered the heavy iron chains with little effort.
Next, the Aesir set to work constructing a new fetter, themselves - one that was twice as thick, and twice as strong. They called this one Dromi - and, when the presented it to Fenrir, the great wolf allowing himself to be bound, once more. Once again, though, Fenrir was able to break free - at this point, the great wolf may even have come to enjoy the game, and waited eagerly to see what the gods would bring to him, next.
In desperation, Odin sent a messenger to the dwarves, asking that they craft a new fetter. The result of their work was Gleipnir - made from the sound a cat makes when it moves, the beard of a woman, the roots of a mountain, the sinew of a bear, the breath of a fish, and the spittle of a bird. While the other fetters had appeared heavy and strong, Gleipnir had the appearance of a thin cord.
As it was presented to Fenrir, though, the great wolf grew suspicious. Fenrir was clever enough to not to be fooled by this new fetter's flimsy appearance - he suspected magic, or some other trick. And so, the Aesir's promise to free him should he prove unable to free himself was no longer enough - Fenrir demanded that one of the Aesir should be willing to place their hand in his mouth, before he would consent to allow himself to be bound, once more.
Of the Aesir, it was only Tyr who was willing to do as the great wolf asked - placing his hand between the great beasts jaws as Fenrir allowed himself to be bound.
While Fenrir had been able to break the previous fetters with little effort, the magic of Gleipnir proved to be too much for him. Fenrir struggled and thrashed, but was unable to free himself - and, as he struggled, the Aesir could only laugh as their plan to restrain the great wolf finally seemed to meet with success. And, through it all, Tyr remained stoic - keeping his hand in place, between the great wolf's jaws.
It seems quite likely that Tyr simply saw this as the honourable thing to do. Tyr may have agreed with the necessity of binding Fenrir, but it was still a betrayal of the great wolf's trust - something which might not have sat well with the honourable deity. It was likely for this reason that Tyr made no effort to withdraw his hand, even as the great wolf finally admitted defeat - and, the Aesir's plan was revealed.
Realising that the Aesir had no intention of setting him free, Fenrir was furious. The great wolf bit down on Tyr's wrist, severing his hand and swallowing it whole. But, he was still bound. And, with Fenrir restrained, the gods of Asgard allowed themselves to rest easy - knowing that they had found a means of pacifying the great beast, and delaying the role that he was destined to play in Ragnarok.
There is an interesting point to be made here, of course. If Loki's monstrous children were such a concern for the Aesir, and if they were destined to play such key roles in the fall of the gods, then why not simply have them killed? It may seem harsh to modern sensibilities, but these were the gods of Vikings - they were not above harsh measures.
The answer to this, though, can be found in the found in the strictly defined concept of fate that can be found in Germanic myths and legends. Much like with the Fates of Greek Mythology, Norse myth held that destiny was overseen by the Norns. No one, not even the gods of Asgard, had to power to defy what the Norns saw - and, while the gift of prophecy possessed by Odin may have allowed them to know their own fate, they did not truly possess the power to change it. Loki's children would live to see Ragnarok because it was already destined that they would - and, this could not be changed.
The fact that the Aesir's efforts to delay Ragnarok had, ultimately, placed each of Loki's monstrous children in the perfect position to play their part is really just one of the strange ironies you tend to get with this concept of destiny. Jormungand would never have been able to grow to such a large size if he had not been cast into the sea. Hel would never have been in a position to prevent the sun god Baldr's return to the world of the living if she had not been banished to Niflheim. And, Fenrir would not have been so utterly consumed by savage rage that he would be willing and able to slay Odin, himself, if he had not been betrayed by the Aesir.