meditate on fire as Brahma

" Fire is, verily, greater than water. For, having seized the air, it warms the akasa. Then people say: 'It is hot, it burns; it will rain.' Thus does fire first manifest itself and then create water. Furthermore, thunderclaps roll with lightning upward and across the sky. Then people say: 'There is lightning, there is thunder; it will rain.' Here also does fire first manifest itself and then create water. Meditate on fire. He who meditates on fire as Brahman becomes radiant himself and obtains radiant worlds, full of light and free from darkness; he can, of his own free will, reach as far as fire reaches, he who meditates on fire as Brahman. Narada said: Venerable Sir,is there anything greater than fire? Of course there is something greater than fire. Please tell that to me, Venerable Sir. "
- Sama Veda, Chandogya Upanishad VII, XI