Bhagavad Gita: Chapter 15, Verse 18

यस्मात्क्षरमतीतोऽहमक्षरादपि चोत्तम: |
अतोऽस्मि लोके वेदे च प्रथित: पुरुषोत्तम: || 18||

yasmāt kṣharam atīto ’ham akṣharād api chottamaḥ
ato ’smi loke vede cha prathitaḥ puruṣhottamaḥ

yasmāthence; kṣharamto the perishable; atītaḥtranscendental; ahamI; akṣharātto the imperishable; apieven; chaand; uttamaḥtranscendental; ataḥtherefore; asmiI am; lokein the world; vedein the Vedas; chaand; prathitaḥcelebrated; puruṣha-uttamaḥas the Supreme Divine Personality


BG 15.18: I am transcendental to the perishable world of matter, and even to the imperishable soul; hence I am celebrated, both in the Vedas and the Smṛitis, as the Supreme Divine Personality.


In the last few verses, Shree Krishna described in detail how the glorious things of nature are all manifestations of His opulence.  However, He does not exhaust Himself in creating the visible universe.  His transcendental personality is beyond both material nature and the divine souls.  Here, He calls His divine personality as Puruṣhottam (Supreme Person). 

One may doubt whether Lord Krishna and the Supreme Being He is referring to are the same.  To remove any such vestiges of misunderstanding, Shree Krishna phrases this verse so as to refer to Himself in the first person singular.  Further, He says that the Vedas too proclaim Him in this manner:

kṛiṣhṇa eva paro devas taṁ dhyāyet taṁ rasayet taṁ yajet taṁ bhajed    

(Gopāl Tāpani Upaniṣhad)

“Lord Krishna is the Supreme Lord.  Meditate upon Him, relish the bliss of His devotion, and worship Him.”  Again:

yo ’sau paraṁ brahma gopālaḥ   (Gopāl Tāpani Upaniṣhad)

“Gopal (Lord Krishna) is the Supreme Being.”  One may then ask about the position of Lord Vishnu, Lord Ram, Lord Shiv, etc.?  They are all different forms of the same Supreme Being, and They are non-different from each other.  As a result, They are all manifestations of Bhagavān, or the Supreme Divine Personality.