। ॥ १३९ ॥
In plain words
Right here is the whole problem: the conviction 'I am this' aimed at what is not the Self. That is the bondage of every person -- born of pure ignorance, and it is exactly what sets off the relentless cycle of birth, death, and every suffering in between. Because of this same conviction, taking an unreal body to be real, a person feeds it, tends it, and guards it -- spinning sense-objects around himself like threads -- the way a silkworm spins and seals itself inside its own cocoon.
Close to the Sanskrit
Here, the notion 'I' toward the non-Self is this person's bondage, arisen from ignorance, the very cause of the onrush of the afflictions of birth and death. By this same notion, taking this unreal body to be real through the sense of self, this person nourishes it, tends it, and protects it with the threads of sense-objects, like the maker of a cocoon.