15.18

यस्मात्क्षरमतीतोऽहम्
अक्षरादपि चोत्तमः ।
अतोऽस्मि लोके वेदे च
प्रथितः पुरुषोत्तमः ॥

yasmāt kṣaram atīto 'ham akṣarād api cottamaḥ
ato 'smi loke vede ca prathitaḥ puruṣottamaḥ

Kṛṣṇa (कृष्ण) continues, and the name of the chapter is the name he claims.

The verse

Because I have gone beyond the perishable, and am higher even than the imperishable, I am celebrated in the world and in the Veda as the supreme person.

नेपालीमा

किनकि म नाशवान्भन्दा पर पुगेको छु र अविनाशीभन्दा पनि उच्च छु, म संसारमा र वेदमा सर्वोच्च पुरुष भनेर प्रसिद्ध छु।

Where it sits

15.16 named two. 15.17 said the highest is another, and that he bears the worlds. This verse says why the name is puruṣottama (पुरुषोत्तम): he is past the perishable and higher than the imperishable. The name is claimed in the world and in the Veda, not only in this talk.

Split: यस्मात् + क्षरम् + अतीतः + अहम् + अक्षरात् + अपि + च + उत्तमः + अतः + अस्मि + लोके + वेदे + च + प्रथितः + पुरुष-उत्तमः

yasmāt + kṣaram + atītaḥ + aham + akṣarāt + api + ca + uttamaḥ + ataḥ + asmi + loke + vede + ca + prathitaḥ + puruṣa-uttamaḥ

Sanskrit, in depth

The words

देवनागरीWordGrammarSense
यस्मात्yasmātablative of yad (यद्)because. Since.
क्षरम्kṣaramaccusative singularthe perishable. Object of atītaḥ (अतीतः).
अतीतःatītaḥnominative singular, past participle of ati-i (अति-इ)gone beyond. Passed.
अहम्ahamnominativeI.
अक्षरात्akṣarātablative singularthan the imperishable. From the imperishable, as the standard one is higher than.
अपिapiindeclinableeven.
चcaindeclinableand.
उत्तमःuttamaḥnominative singularhigher. Supreme.
अतःataḥindeclinabletherefore.
अस्मिasmipresent, 1st singular of as (अस्)I am.
लोकेlokelocative singularin the world.
वेदेvedelocative singularin the Veda.
चcaindeclinableand.
प्रथितःprathitaḥnominative singular, past participle of prath (प्रथ्)celebrated. Declared abroad.
पुरुष-उत्तमःpuruṣa-uttamaḥnominative singularthe supreme person. puruṣa (पुरुष) is the person. uttama (उत्तम) is highest.

The phrases

यस्मात् क्षरम् अतीतः अहम् yasmāt kṣaram atītaḥ aham is the first reason. Because I have gone beyond the perishable. kṣaram (क्षरम्) is accusative, the thing crossed. अतीतः + अहम् atītaḥ + aham is atīto 'ham (अतीतोऽहम्). Said straight through, the m (म्) of aham (अहम्) joins the next quarter: aham akṣarād api (अहमक्षरादपि).

अक्षरात् अपि च उत्तमः akṣarāt api ca uttamaḥ is the second reason, and it is a comparison. And I am higher even than the imperishable. अक्षरात् + अपि akṣarāt + api is akṣarād api (अक्षरादपि), t (त्) before a vowel becoming d (द्). च + उत्तमः ca + uttamaḥ is cottamaḥ (चोत्तमः), अ + उ a + u becoming o (ओ).

अतः अस्मि लोके वेदे च प्रथितः पुरुषउत्तमः ataḥ asmi loke vede ca prathitaḥ puruṣa-uttamaḥ is the name that follows. Therefore I am celebrated in the world and in the Veda as the supreme person. अतः + अस्मि ataḥ + asmi is ato 'smi (अतोऽस्मि). पुरुष + उत्तमः puruṣa + uttamaḥ is puruṣottamaḥ (पुरुषोत्तमः).

Sanskrit in this line

akṣarāt (अक्षरात्) is ablative singular, and with uttamaḥ (उत्तमः) it answers "than." Higher than the imperishable. Do not read it as the place he comes from. The perishable is handled differently in the same line: kṣaram (क्षरम्) is accusative with atītaḥ (अतीतः), "gone beyond" the thing named in the accusative. Two cases, two relations, one verse.

Say it back

Beyond the perishable, higher than the imperishable, and the name. If the ablative akṣarāt (अक्षरात्) is said as a nominative, he is no longer higher than it. Stay here.