Bg 15.18

yasmat ksaram atito ’ham
aksarad api cottamah
ato ’smi loke vede ca
prathitah purusottamah

Word for word: 
yasmat — because; ksaram — to the fallible; atitah — transcendental; aham — I am; aksarat — beyond the infallible; api — also; ca — and; uttamah — the best; atah — therefore; asmi — I am; loke — in the world; vede — in the Vedic literature; ca — and; prathitah — celebrated; purusa-uttamah — as the Supreme Personality.

Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Because I am transcendental, beyond both the fallible and the infallible, and because I am the greatest, I am celebrated both in the world and in the Vedas as that Supreme Person.

Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
No one can surpass the Supreme Personality of Godhead, Krishna – neither the conditioned soul nor the liberated soul. He is therefore the greatest of personalities. Now it is clear here that the living entities and the Supreme Personality of Godhead are individuals. The difference is that the living entities, either in the conditioned state or in the liberated state, cannot surpass in quantity the inconceivable potencies of the Supreme Personality of Godhead. It is incorrect to think of the Supreme Lord and the living entities as being on the same level or equal in all respects. There is always the question of superiority and inferiority between their personalities. The word uttama is very significant. No one can surpass the Supreme Personality of Godhead.

The word loke signifies “in the paurusa agama (the smrti scriptures).” As confirmed in the Nirukti dictionary, lokyate vedartho ’nena: “The purpose of the Vedas is explained by the smrti scriptures.”

The Supreme Lord, in His localized aspect of Paramatma, is also described in the Vedas themselves. The following verse appears in the Vedas (Chandogya Upanisad 8.12.3): tavad esa samprasado ’smac charirat samutthaya param jyoti-rupam sampadya svena rupenabhinispadyate sa uttamah purusah. “The Supersoul coming out of the body enters the impersonal brahma-jyotir; then in His form He remains in His spiritual identity. That Supreme is called the Supreme Personality.” This means that the Supreme Personality is exhibiting and diffusing His spiritual effulgence, which is the ultimate illumination. That Supreme Personality also has a localized aspect as Paramatma. By incarnating Himself as the son of Satyavati and Parasara, He explains the Vedic knowledge as Vyasadeva.