Sankaracarya's Vivekachudamani 496

सर्वेषु भूतेष्वहमेव संस्थितो

ज्ञानात्मनान्तर्बहिराश्रयः सन् ।

भोक्ता च भोग्यं स्वयमेव सर्वं

यद्यत्पृथग्दृष्टमिदन्तया पुरा ॥

sarveṣu bhūteṣvahameva saṃsthito

jñānātmanāntarbahirāśrayaḥ san |

bhoktā ca bhogyaṃ svayameva sarvaṃ

yadyatpṛthagdṛṣṭamidantayā purā ||

(Sankaracarya's Vivekachudamani 496)

I am the sole reality residing in all beings in the form of Knowledge. Being their external and internal support, I myself am the experiencer and the experienced; I am all that was previously experienced by me distinctly as 'this' and 'not-this.'

In this sloka Sripad Sankaracarya explaining that he is Brahman himself. He is residing in all living beings as a Knowledge that can show the path to Supreme Lord. He is a guru who lives with us by supporting us externally and internally. So there is no such guru who can be our guide. He is specifically an experience. all those who experience the presence of the creator should be experienced through him. He is the real distinction that can lead to liberation.