। ॥ १५१ ॥
In plain words
The Self does not shine clearly when it is covered by the five sheaths born of its own power, starting with the sheath made of food -- just as the water of a pond stops shining once it grows its own covering of moss, moss it fed into being with its own nourishing power.
Close to the Sanskrit
The Self, covered by the five sheaths born of its own power, beginning with the food-sheath, does not shine forth clearly, just as water sitting in a pond does not shine forth when covered by layers of moss generated from its own power.