In plain words
A cloud obscures someone's view, and they think the sun has lost its light. In the same way, to the eyes of the deluded the Self seems wholly bound, though it never moves. I am that unchanging Self, ever established.
Word for word
As an ignorant person, whose sight is obscured by a cloud, supposes that the sun has been covered and lost its light, He appears wholly bound from the ignorant person's viewpoint alone. I am that unchanging, ever-established Self.