Can Silk Stop an Arrow?

So, silk was useful for later removing the arrow because the silk wrapping over the arrowhead made it easier to slide out of the wound. This means that although silk is strong enough to not tear when an arrow is shot at it, it doesn't stop the arrow.

Why did the Mongols wear silk?

Mongol warriors wore silk to protect them from swords and arrows. The ancient Mongol warriors wore Chinese silk underwear beneath their armour and it wasn't just for its warmth and comfort. This underwear gave substantial protection from knives, swords and arrows.

Can you stab silk?

If you think about it, if all you wore was said silk, you'd still get a hole from a knife, it just wouldn't be as precise or as deep. The flexibility of the cloth would wrap around the knife and happily puncture the body. However, this stuff would make great hot air balloon material.