यस्मात्क्षरमतीतोऽहमक्षरादपि चोत्तम: |
अतोऽस्मि लोके वेदे च प्रथित: पुरुषोत्तम: || 18||
yasmāt kṣharam atīto ’ham akṣharād api chottamaḥ
ato ’smi loke vede cha prathitaḥ puruṣhottamaḥ
yasmāt—hence; kṣharam—to the perishable; atītaḥ—transcendental; aham—I; akṣharāt—to the imperishable; api—even; cha—and; uttamaḥ—transcendental; ataḥ—therefore; asmi—I am; loke—in the world; vede—in the Vedas; cha—and; prathitaḥ—celebrated; puruṣha-uttamaḥ—as the Supreme Divine Personality
As I surpass the Perishable and as I am higher even than the Imperishable, I am extolled in the world and in the Vedas as the Supreme Self.
Paramatma is called the Highest Purusha, because he transcends the perishable body and the imperishable Jiva. The Jiva should go beyond his limited jivatvam-imprisonment in the cell of the body and mind-vehicles and attain his true nature as the Highest Purusha. In truth, jivatvam is an illusion. The Jiva is no other than the Supreme Purusha.
Question: Why is Paramatma declared to be the highest Purusha?
Answer: Because He is higher than the perishable body (Kshara) and the Jiva (Aksharam).