Answer:
Put into a pit, locked beneath a grate, guarded through the night, yet it still goes out.
You will find me with four legs, but no hair. People ride me for hours, but I don't go anywhere without needing to be tugged. Jerked or turned on, I always manage to be ready for work.
This is needed both for courage and hardcover books.
The sharp slim blade, that cuts the wind.
Ten men's strength, ten men's length. Ten men can't break it, yet a young boy walks off with it.
I’m grown from darkness but shine with a pale light. Very round I am and always a lady's delight.