नैमिषोपाख्यानं नाम तृतीयोऽध्यायः
Naimisharanya episode Chapter 3
Lord Brahma said (to the sages)
एको देवो महादेवो विज्ञेयस्तु महेश्वरः |
न तस्य परमं किञ्चित्पदं समधिगम्यते || 15 ||
The one Deva, the great Deva should really be known as the great God. No level above his can be reached (no level above his exists).