The name and identity of Brahma - Kaushitaki Brahmana Upanishad, First Adhyaya

Know the male names of Brahma by breathing (prana). Know the female names of Brahma by speaking (vak). Know the names of Brahma which are neither male nor female, and both male and female, by mindfulness and good conscience (manas). Know the smell of Brahma by your nose; know the form of Brahma by your eye; know the sound of Brahma's voice by your ear; know the flavor of Brahma by your tongue as it tastes your food; know the actions of Brahma by what your hands do; know what gives Brahma pleasure and pain by your body; know the joy and children of Brahma by your own; know the path of Brahma by the path your feet have taken; know the thought of Brahma - Brahma's desire - by wisdom and prudence (prajna). Know the victory of Brahma by understanding this.

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!