Sarve veda padam amananti, tapamsi sarvani-ca yad vdanti Yad icchanto brahmacharyam caranti, tat te padam samgrahenabravimi om iti etat
All the words in veda refer to same, all the tapsvi say the same, it gives whatever the wishes of brahmachari that is the same as OM.
- Katha Upanishad 2.15 sloka
In Geetha he refers to OM vibuthi adhyaya
maharṣīṇāṃ bhṛgurahaṃ girāmasmyekamakṣaram।
yajñānāṃ japayajño'smi sthāvarāṇāṃ himālayaḥ ।10.25
Of great sages I am Bhrigu. Of sounds I am the monosyllabic mantra Om. Of sacrifices I am japa. Of immovable things I am the Himalayas.
सर्वस्य चाहं हृदि सन्निविष्टो
मत्त: स्मृतिर्ज्ञानमपोहनं च |
वेदैश्च सर्वैरहमेव वेद्यो
वेदान्तकृद्वेदविदेव चाहम् || 15||
sarvasya chāhaṁ hṛidi sanniviṣhṭo
mattaḥ smṛitir jñānam apohanaṁ cha
vedaiśh cha sarvair aham eva vedyo
vedānta-kṛid veda-vid eva chāham
BG 15.15: I am seated in the hearts of all living beings, and from Me come memory, knowledge, as well as forgetfulness. I alone am to be known by all the Vedas, am the author of the Vedānt, and the knower of the meaning of the Vedas.
By induction a->b Krishna -> OM single letter By katha upanishad All words are OM Krishna-> OM <- All words in Veda(Katha upanishad) in other words Krishna -> all words in veda -> OM is same. This was stated by madvacharya. Madvacharya even goes further all the sounds refer to him only not only veda..
Jai Madhva gurave namaha.. Jai sri krishna