Myths of the Norsemen From the Eddas and Sagas
Page: 54When it was time to drink this toast, which was served in cups shaped like a ship, and was called the Bragaful, the sacred sign of the hammer was first made over it. Then the new ruler or head of the family solemnly pledged himself to some great deed of valour, which he was bound to execute within the year, unless he wished to be considered destitute of honour. Following his example, all the guests were then wont to make similar vows and declare what they would do; and as some of them, owing to previous potations, talked rather too freely of their intentions on these occasions, this custom seems to connect the god’s name with the vulgar but very expressive English verb “to brag.”
In art, Bragi is generally represented as an elderly man, with long white hair and beard, and holding the golden harp from which his fingers could draw such magic strains. 
Chapter VII: Idun
The Apples of Youth
Idun, the personification of spring or immortal youth, who, according to some mythologists, had no birth and was never to taste death, was warmly welcomed by the gods when she made her appearance in Asgard with Bragi. To further win their affections she promised them a daily taste of the marvellous apples which she bore in her casket, and which had the power of conferring immortal youth and loveliness upon all who partook of them.
“The golden apples
Out of her garden
Have yielded you a dower of youth,
Ate you them every day.”
Wagner (Forman’s tr.).
Thanks to this magic fruit, the Scandinavian gods, who, because they sprang from a mixed race, were not all immortal, warded off the approach of old age and disease, and remained vigorous, beautiful, and young through countless ages. These apples were therefore considered very precious indeed, and Idun carefully treasured them in her magic casket. No matter how many she drew out, the same number always remained for distribution at the feast of the gods, to whom alone she vouchsafed a taste, although dwarfs and giants were eager to obtain possession of the fruit.
“Bright Iduna, Maid immortal!
Standing at Valhalla’s portal,
In her casket has rich store
Of rare apples gilded o’er;
Those rare apples, not of Earth,
Ageing Æsir give fresh birth.”
Valhalla (J. C. Jones). 
The Story of Thiassi
One day, Odin, Hoenir, and Loki started out upon one of their usual excursions to earth, and, after wandering for a long while, they found themselves in a deserted region, where they could discover no hospitable dwelling. Weary and very hungry, the gods, perceiving a herd of oxen, slew one of the beasts, and, kindling a fire, they sat down beside it to rest while waiting for their meat to cook.
Loki and Thiassi
To their surprise, however, in spite of the roaring flames the carcass remained quite raw. Realising that some magic must be at work, they looked about them to discover what could hinder their cookery, when they perceived an eagle perched upon a tree above them. Seeing that he was an object of suspicion to the wayfarers, the bird addressed them and admitted that he it was who had prevented the fire from doing its accustomed work, but he offered to remove the spell if they would give him as much food as he could eat. The gods agreed to do this, whereupon the eagle, swooping downward, fanned the flames with his huge wings, and soon the meat was cooked. The eagle then made ready to carry off three quarters of the ox as his share, but this was too much for Loki, who seized a great stake lying near at hand, and began to belabour the voracious bird, forgetting that it was skilled in magic arts. To his great dismay one end of the stake stuck fast to the eagle’s back, the other to his hands, and he found himself dragged over stones and through briers, sometimes through the air, his arms almost torn out of their sockets. In vain he cried for mercy and implored the eagle to let him go; the bird flew on, until he promised any ransom his captor might ask in exchange for his release.