Four Mahavakyas in Upnishads

In 11 principle Upnishads, Sri Shankaracharya explain the deepest reality of this universe which are guaranteed to alleviate the delusive dual and divided consciousness of any sincere seeker to undivided and universal consciousness. There are four Mahavakyas (great statements) which contain the complete description of unstained reality of seekers consciousness in meditative state as well as after liberation or being one with the infinite consciousness. Just contemplating on these four great statement could be mean to open to new level of consciousness which can exponentially raise our awareness to cut the bondage of misery and to experience the ultimate bliss of samadhi. Here are four great statement and there occurrence as well as there nature of influence on the consciousness.

1. प्रज्ञानं ब्रम्हा (Pragyanam Brahma) means "the self, the consciousness is Brahmans*" or "knowledge (Pragya) is Brahman" (since self itself is all knowing intelligence therefore both the meanings indicate same thing in principle which is all knowing self is Brahman). It has been explained in Aitreya Upnishad and its called लक्षण वाक्य (Lakshana vakya) means which explain the characteristic of Brahman.

2. तत् त्वं असि (Tat tram asi) means "that thou art". It has been explained in Chandogya Upnishad and its called उपदेश वाक्य (Updesha vakya) means which tell the detailed instruction for a seeker about the nature of Brahman.

3. अयं आत्मा ब्रम्हा (Ayam Atma Brahma) means "the self is Brahman". It has been explained in Munduka Upnishad and it's called अनुभव वाक्य (anubhav vakya) means it comes from the direct experience when seeker consciousness unite with Brahman.

4. अहम् ब्रह्मास्मि (Aham brahmasmi) mean "I am Brahman". It has been explained in Brhadaranyaka Upnishad and it's called प्रस्ताव वाक्य (prasthav vakya) means it comes as suggestive statement after merging with the Brahman.

*Brahman is the unchanging, infinite, immanent, and transcendent reality which is the Divine Ground of all matter, energy, time, space, being, and everything beyond in this Universe.