Lines 399-401:
Then spoke the thunder
Da
Datta: what have we given?
Eliot's Note:
401. “Datta, dayadhvam, damyata” (Give, sympathise, control). The fable of the meaning of the Thunder is found in the Brihadaranyaka—Upanishad, 5, 1. A translation is found in Deussen's Sechsig Upanishads des Veda, p. 489.
Context:
The Upanishads are a collection of Hindu scriptures. A translation of the fable of the Thunder is available on the reference page.