17.24 Therefore, when performing acts of sacrifice, offering charity, or undertaking penance, expounders of the Vedas always begin by uttering “Om” according to the prescriptions of Vedic injunctions.
The syllable Om is a symbolic representation of the impersonal aspect of God. It is also considered as the name for the formless Brahman . It is also the primordial sound that pervades creation. Its proper pronunciation is “Aaa” with the mouth open, “Ooh” with the lips puckered, and “Mmm” with the lips pursed. It is placed in the beginning of many Vedic mantras as a bīja (seed) mantra to invoke auspiciousness.