BHAGAVADGITA | 15.17 | SRI ADI SANKARACARYA
uttamah purusas tv anyah paramatmety udahrtah
yo loka-trayam avisya bibharty avyaya isvarah || 15.17 ||
15.17 But different is the Supreme Person who is spoken of as the transcendental Self , who , permeating the three worlds , upholds ( them ) , and is the imperishable GOD .
|| BHASYA || Tu , but ; anyah , different , entirely contrary in characteristics from these ; is the uttamah , supreme , most excellent ; purusah , Person , who is different in characteristics from these — the mutable and the immutable — , untouched by the mutable and the immutable limiting adjuncts , and is by nature eternal , pure , conscious and free ; udahrtah , spoken of in the Upanisads ; iti , as ; the paramatma , Supreme Self ; IT is paramah , supreme , as compared with the selves like body etc created by ignorance , and is the Atma , Self , the inmost Consciousness of all beings .
Hence IT is the Supreme Self . IT ITSELF is being specially described : yah , who , by dint of ITs own active power inhering in the energy that is Maya * ; avisya , permeating ; loka-trayam , the three worlds — called Bhuh ( Earth ) , Bhuvah , ( Intermediate Space ) and Svah ( Heaven ) ; bibharti , upholds ( them ) by merely being present in ITs own nature . ( And IT ) is the avyayah , imperishable ; Isvarah , GOD , the Omniscient One called Narayana , who is the Lord by nature .
This name — the Supreme Person of GOD as described is well known . Showing that the name is apt by virtue of its etymological significance , the Lord reveals Itself saying ,
" I am the unsurpassable GOD "
( NOTE : * Caitanya , Consciousness , Itself is the bala ( energy ) ; the sakti ( active power ) therein is Maya . Through that IT upholds . )
SOURCE | SATYAVEDISM.COM