स यावदादित्यः पुरस्तादुदेता पश्चादस्तमेता द्विस्तावद्दक्षिणत उदेतोत्तरतोऽस्तमेता रुद्राणामेव तावदाधिपत्यं स्वाराज्यं पर्येता ॥ ४ ॥
In plain words
For as long as the sun rises in the east and sets in the west, and for twice that duration rises in the south and sets in the north—for that long he attains the supreme dominion and self-rule of the Rudras.
Close to the Sanskrit
As long as the sun rises in the east and sets in the west, twice that long it rises in the south and sets in the north: to that extent he attains the lordship and self-rule of the Rudras.