"The goal which all the Vedas declare, which all austerities aim at, and which men desire when they lead the life of continence … is AUM.
This syllable AUM is indeed Brahman.
Whosoever knows this syllable obtains all that he desires.
This is the best support; this is the highest support.
Whosoever knows this support is adored in the world of Brahma."
~ Katha Upanishad (I)