BG 17.23

17.23 तत्सत् Om Tat Sat? इति thus? निर्देशः designation? ब्रह्मणः of Brahman? त्रिविधः threefold? स्मृतः has been declared? ब्राह्मणाः Brahmanas? तेन by that? वेदाः Vedas? च and? यज्ञाः sacrifices? च and? विहिताः created? पुरा formerly.Commentary Om Tat Sat is the root of the entire universe. Om is the Akshara Brahman. Tat means Thath? the indefinable. Sat means Reality.Para Brahman? that Supreme Being? the abiding place of all that lives and moves? is beyond name and class. The Vedas have ventured to give a name to Him. A new born child has no name but no,receiving one he will answer to it. Men who are troubled by the afflictions of this world run to the Deity for refuge and call Him by the name. When Brahman is invoked through the name that which is hidden is revealed to the aspirant.These three words have a divine power of their own. The vibrations that they produce in one are such as to arouse the latent divinity and also to secure the necessary response from the Cosmic Being Whom they connote.When a sacrificial rite or the like is found defective? it will be rendered perfect by the utterance of the powerful Mantra Om Tat Sat or one of the three designations in the end. With Om or Om Tat Sat all acts of sacrifice? study of sacred scriptures? spiritual discipline and meditation are commenced. If the doer of sacrifices remembers either of these Mantras all obstacles that stand in the way of success of the sacrifices are removed.Om Tat Sat has been declared to be the triple designation of Brahman in the Vedanta by the knowers of Brahman. The power of creation that lies in the Creator emanates from this Mantra. When He meditated inwardly on the meaning of this Mantra and repeated the threefold word? He acired the power to create. Then He created the Brahmanas? gave them the Vedas to be their guide and directed them to perform sacrifices and other rites.Puraa Of old At the beginning of creation by the Prajapati.Brahman here means the Veda.

— vedicscriptures · exposition · source ↗

It has been explained that penance, sacrifice, charity and foods are divided into three categories: the modes of goodness, passion and ignorance. But whether first class, second class or third class, they are all conditioned, contaminated by the material modes of nature. When they are aimed at the Supreme – oṁ tat sat, the Supreme Personality of Godhead, the eternal – they become means for spiritual elevation. In the scriptural injunctions such an objective is indicated. These three words, oṁ tat sat, particularly indicate the Absolute Truth, the Supreme Personality of Godhead. In the Vedic hymns, the word oṁ is always found. One who acts without following the regulations of the scriptures will not attain the Absolute Truth. He will get some temporary result, but not the ultimate end of life. The conclusion is that the performance of charity, sacrifice and penance must be done in the mode of goodness. Performed in the mode of passion or ignorance, they are certainly inferior in quality. The three words oṁ tat sat are uttered in conjunction with the holy name of the Supreme Lord, e.g., oṁ tad viṣṇoḥ. Whenever a Vedic hymn or the holy name of the Supreme Lord is uttered, oṁ is added. This is the indication of Vedic literature. These three words are taken from Vedic hymns. Oṁ ity etad brahmaṇo nediṣṭhaṁ nāma indicates the first goal. Then tat tvam asi ( Chāndogya Upaniṣad 6.8.7) indicates the second goal. And sad eva saumya ( Chāndogya Upaniṣad 6.2.1) indicates the third goal. Combined they become oṁ tat sat. Formerly when Brahmā, the first created living entity, performed sacrifices, he indicated by these three words the Supreme Personality of Godhead. Therefore the same principle has always been followed by disciplic succession. So this hymn has great significance. Bhagavad-gītā recommends, therefore, that any work done should be done for oṁ tat sat, or for the Supreme Personality of Godhead. When one performs penance, charity and sacrifice with these three words, he is acting in Kṛṣṇa consciousness. Kṛṣṇa consciousness is a scientific execution of transcendental activities which enables one to return home, back to Godhead. There is no loss of energy in acting in such a transcendental way.

— vedicscriptures · exposition · source ↗