The name and identity of Brahma - Kaushitaki Brahmana Upanishad, First Adhyaya
Who is Brahma? Brahma is that which is, that which is true (sat-tyam). What is true? What is not true (sat) is sensed (tyam); what is true is whatever remains, whatever is not-untrue, whatever You are. For indeed, I am Brahma; I am You - and You are Me!