यो विज्ञाने तिष्ठन् विज्ञानादन्तरो यं विज्ञानं न वेद यस्य विज्ञानं शरीरं यो विज्ञानमन्तरो यमयत्येष त आत्मान्तर्याम्यमृतः ॥बृह. ३,७.२२ ॥
In plain words
He who dwells in understanding, yet is within understanding, whom understanding does not know, whose body understanding is, who from within controls understanding — he is thy Self, the inner controller, the immortal.