Verse 3.8.4

स यावदादित्यो दक्षिणत उदेतोत्तरतोऽस्तमेता द्विस्तावत्पश्चादुदेता पुरस्तादस्तमेतादित्यानामेव तावदाधिपत्यंस्वाराज्यं पर्येता ॥ ३.८.४ ॥
॥ इति अष्टमः खण्डः ॥

sa yāvadādityo dakṣiṇata udetottarato'stametā dvistāvatpaścādudetā purastādastametādityānāmeva tāvadādhipatyaṃsvārājyaṃ paryetā || 3.8.4 ||
|| iti aṣṭamaḥ khaṇḍaḥ ||

4. As long as the sun rises in the south and sets in the north, twice that long will he [who knows this] rise in the west and set in the east. That person will also attain sovereignty and freedom like the Ādityas.

Word-for-word explanation:

Yāvat, so long as; ādityaḥ, the sun; dakṣiṇataḥ udetā, rises in the south; uttarataḥ astam-etā, [and] sets in the north; saḥ, he [who knows this]; dviḥ-tāvat, twice that long; paścāt udetā, will rise in the west; purastāt astam-etā, [and] set in the east; eva tāvat, that long; ādityānām, of the Ādityas; ādhipatyam, sovereignty; svārājyam, freedom; pari-etā, will attain. Iti āṣṭamaḥ khaṇḍaḥ, here ends the eighth section.

Commentary:

The sun neither rises nor sets; it is always stationary. It merely gives the impression of rising and setting.