Weaving and spinning, once basic household tasks for every woman, have more links to magic, myth and lore than any other craft.

Nornir and Babies
In Northern European Mythology it was the Nornir that spun the Wyrd of Gods and Men (in this context, the word Wyrd is more accurately translated as 'doom' or 'death') and as such, there are many folk traditions concerned with ensuring a good fate for the child. Some even go as far as to keep the woman from all spinning and weaving activities so as not to inadvertantly affect the fate of the child in anyway. One custom practiced by Swedish women is particularly of note:

This belief led to rituals performed by Swedish women, who in the seventh month of pregnancy drew blood from their finger with a sewing needle, and used it to mark a strip of wood with protective symbols. Then she spun three lengths of linen thread, which were dyed red, black, and one left white. The wooden strip was burned, and its ashes mixed with mead or beer. A burning twig from the fire was used to burn apart seven inch lengths from each of the linen threads, which were then boiled in salted water and left to dry in the forest on the limb of a tree for three days. These were then wrapped in clean linen and saved until the day of birth. The white cord was used to tie off the umbilical cord of the newborn. The red was tied around the baby's wrist as a protective amulet, sometimes strung with a bead to repel the evil eye. And the black , symbolic of death and ill-luck, was burned to ash and the ashes buried. Often the afterbirth was buried beneath the tree on which the linen threads had dried.

For magical purposes, spindles were made out of different materials so as to add to the magical properties of the thread being spun. Some spindles have been found made of rock crystals and others, have been found made of amber and jet (otherwise known back then as black amber).

Battle Magic and Causing Death
Given the life and death importance linked to spinning, maybe it comes as no surprise that weaving, the usual goal of spinning was used in battle magic among the Northern Europeans. There are two very well known examples of weaving as battle magic to be found in the sagas. Perhaps the most famous is that of the Raven Banner which was described in the Orkneyingarsaga as:

One summer it happened that a Scottish earl called Finnleik challenged Sigurðr to fight him on a particular day at Skitten. Sigurðr's mother was a sorceress so he went to consult her, telling her that the odds against him were heavy, at least seven to one.'Had I thought you might live forever,' she said, 'I'd have reared you in my wool-basket. But lifetimes are shaped by what will be, not by where you are. Now, take this banner. I've made it for you with all the skill I have, and my belief is this: that it will bring victory to the man it's carried before, but death to the one who carries it.' It was a finely made banner, very cleverly embroidered with the figure of a raven, and when the banner fluttered in the breeze, the raven seemed to be flying ahead.Earl Sigurðr lost his temper at his mother's words. He got the support of the Orkney farmers by giving them back their land-rights, then set out for Skittern to confront Earl Finnleik. The two sides formed up, but the moment they clashed Sigurðr's standard-bearer was struck dead. The Earl told another man to pick up the banner but before long he'd been killed too. The Earl lost three standard bearers, but he won the battle and the farmers of Orkney got back their land rights.

Also in the Orkneyingarsaga is the account of a shirt that was woven with either poison or killing magic:

...the sisters pulled off their bonnets, tore their hair and said that if he put on the garment his life would be at risk. Though they were both in tears he didn't let that stop him, but no sooner was the garment upon his back than his flesh started to quiver and he began to suffer terrible agony. He had to go to bed and not long after that he died.
So fundamental is the connection between weaving, death and fate in this worldview that not only is weaving oft used as a metaphor for fate but it was also used as part of a description of Valkyries on the battlefield and their craft.

Blood rains from the cloudy webOn the broad loom of slaughter.The web of man grey as armorIs now being woven; the ValkyriesWill cross it with a crimson weft.The warp is made of human entrails;Human heads are used as heddle-weights;The heddle rods are blood-wet spears;The shafts are iron-bound and arrows are the shuttles.With swords we will weave this web of battle.The Valkyries go weaving with drawn swords,Hild and Hjorthrimul, Sanngrid and Svipul.Spears will shatter shields will splinter,Swords will gnaw like wolves through armor.Let us now wind the web of warWhich the young king once waged.Let us advance and wade through the ranks,Where friends of ours are exchanging blows.Let us now wind the web of warAnd then follow the king to battleGunn and Gondul can see thereThe blood-spattered shields that guarded the king.Let us now wind the web of warWhere the warrior banners are forging forwardLet his life not be taken;Only the Valkyries can choose the slain.Lands will be ruled by new peoplesWho once inhabited outlying headlands.We pronounce a great king destined to die;Now an earl is felled by spears.The men of Ireland will suffer a griefThat will never grow old in the minds of men.The web is now woven and the battlefield reddened;The news of disaster will spread through lands.It is horrible now to look aroundAs a blood-red cloud darkens the sky.The heavens are stained with the blood of men,As the Valyries sing their song.We sang well victory songsFor the young king; hail to our singing!Let him who listens to our Valkyrie songLearn it well and tell it to others.Let us ride our horses hard on bare backs,With swords unsheathed away from here!And then they tore the woven cloth from the loom and ripped it to pieces, each keeping the shred she held in her hands... The women mounted their horses and rode away, six to the south and six to the north.
Weaving was also used in protective and healing magic and there are two accounts of women weaving protective shirts for their loved ones.

Spinning, Weaving and the Law

During and after the conversion period, women were encouraged not to:

name other unfortunate persons either at the loom, or in dyeing, or in any kind of work with textiles
-Elgius of Noyon

While Corrector of Burchard of Worms, ca. 1010, set the following penance for magical weaving:

Have you been present at or consented to the vanities which women practice in their woollen work, in their weaving, who when they begin their weaving hope to be able to bring it about that with incantations and with their actions that the threads of the warp and the woof become so intertwined that unless someone makes use of these other diabolical counter-incantations, he will perish totally? If you have been present or consented, you must do penance for thirty days on bread and water