As she stands above, before her descent, the soul steps higher each day. And that is a prison, because the soul is G-dly and G-dly means infinite and for a G–dly being, stepping higher each day is standing still.
But the soul is blind to her own prison. So she must descend below, and there she will experience the ultimate confines of a body and of the animal--and she will transform that animal to yearn with a divine yearning.
Only then will she learn to leap, to break out of all boundaries, to escape the prison of being.