These mahavakyas, in the light of which the Upanisads should be understood according to the hermeneutical tradition of Advaita Vedanta, are the following:
I. All this is verily Brahman.
II. I am Brahman.
III. This Atman is Brahman.
IV. That thou art.
To this a fifth is sometimes added:
V. Brahman is spirit (or consciousness). (Arvind Sharma, 2004, pp. 18-19)
https://en.wikipedia.org/wiki/Mah%C4%81v%C4%81kyas
Mahāvākyas 是《奧義書》中的“偉大聖言”，以吠檀多不二論學派為特徵，其中 mahā 意為“偉大”，vākya 意為“句子”。最常見的是，大佛家的數量被認為是四位， 與其他大佛一樣，它也解釋了梵與阿特曼的統一，這是吠檀多不二論的基本原則
The Mahāvākyas (sing.: mahāvākyam, महावाक्यम्; plural: mahāvākyāni, महावाक्यानि) are "The Great Sayings" of the Upanishads, as characterized by the Advaita school of Vedanta with mahā meaning great and vākya, a sentence. Most commonly, Mahāvākyas are considered four in number,[1][2]
Like other Mahāvākyas, it also explains the unity of Brahman and Atman, which is the basic principle of Advaita Vedanta.[3]
- Tat Tvam Asi (तत् त्वम् असि) - traditionally interpreted as "That Thou Art" (that you are),[4][5][6] (Chandogya Upanishad 6.8.7 of the Sama Veda, with tat in Ch.U.6.8.7 referring to sat, "the Existent"[7][8][9]); correctly translated as "That's how [thus] you are,"[4][6][10][11] with tat in Ch.U.6.12.3 referring to "the very nature of all existence as permeated by [the finest essence]"[12][13]
- Ahaṁ Brahmāsmi (अहं ब्रह्मास्मि) - "I am Brahman", or "I am Divine"[14](Brihadaranyaka Upanishad 1.4.10 of the Yajur Veda)
- Prajñānaṁ Brahma (प्रज्ञानं ब्रह्म) - "Prajñāna[note 1] is Brahman"[note 2], or "Brahman is Prajñāna"[web 2] (Aitareya Upanishad 3.3 of the Rig Veda)
- Ayam Ātmā Brahma (अयम् आत्मा ब्रह्म) - "This Self (Atman) is Brahman" (Mandukya Upanishad 1.2 of the Atharva Veda)
Those statements are interpreted as supporting the insight that the individual self (jīvá) which appears as a separate existence, is in essence (ātmán) part and manifestation of the whole (Brahman).
https://www.swamij.com/mahavakyas.htm
Mahavakyas: The Great Contemplations
