Ribhu Gita

The Self alone is the spontaneous self effulgent Awareness; 
that alone is eternal bliss; 
that alone is Existence everlasting; that alone is all embracing perfection; the sole God-head without a rival and the sole primordial stuff of the Universe. 

In the conviction born of this experience, one should ever abide, as the sole I-AM, the Supreme Self.

Essence of Ribhu Gita Ch. 17, v. 29