Then the demons said to him: Please instruct us, Sir. To them he uttered the same syllable da and asked: Have you understood? They replied: We have. You said to us: ’Be compassionate (dayadhvam).’ He said: Yes, you have understood. That very thing is repeated even today by the heavenly voice, in the form of thunder, as Da, Da, Da, which means: Control yourselves, Give, and Have compassion. Therefore one should learn these three: self-control, giving and mercy.
Yajur Veda, Brihadaranyaka Upanishad V, II-The Three Great Disciplines, 3
Prajapati is this-the heart (intellect). It (the heart) is Brahman. It is all. Hridayam (the heart) consists of three syllables. One syllable is hri; and to him who knows this, his own people and others bring presents. One syllable is da; and to him who knows this, his own people and others give their powers. One syllable is yam; and he who knows this goes to heaven.
Yajur Veda, Brihadaranyaka Upanishad V, III-Brahman as the Heart, 1
That intellect Brahman was verily this-satya alone. And whosoever knows this great, glorious first-born one as the Satya Brahman conquers these worlds. And his enemy is thus conquered and becomes non-existent-yes, whosoever knows this great, glorious first-born one as the Satya Brahman; for Satya indeed is that Brahman.
Yajur Veda, Brihadaranyaka Upanishad V, IV-Meditation on Satya Brahman, 1
In the beginning this universe was water alone. That water produced Satya. Satya is Brahman. Brahman produced Prajapati and Prajapati the gods. Those gods meditate on Satya. This name Satya consists of three syllables. Sa is one syllable, ti is one syllable, and ya is one syllable. The first and last syllables are the truth. In the middle is untruth. This untruth is enclosed on both sides by truth; thus truth preponderates. Untruth does not hurt him who knows this.
Yajur Veda, Brihadaranyaka Upanishad V, V-In Praise of Satya Brahman, 1
Now, that which is Satya is the sun-the being who dwells in yonder orb and the being who is in the right eye. These two rest on each other. The former (the being in the sun) rests on the latter (the being in the right eye) through his rays and the latter rests on the former through his organs. When the individual self is about to leave the body, he sees the solar orb clearly (i.e. without rays). Those rays no longer come to him.
Yajur Veda, Brihadaranyaka Upanishad V, V-In Praise of Satya Brahman, 2
