Upanishads and Gita, ring in unison at “OM” being the primordial sound of this entire universe. The vibration of OM is the source of manifestation. Chanting OM strikes a note on every strand of the vocal cord.

Hindu rituals and practices start with OM, the harbinger of divinity. There could be variations in rituals and practices but unity in their commencement.

Upanishads declare with authority that OM represents the all-pervading divinity. Krishna in the Gita says the chant om tat sat ( divinity here, divinity there, divinity everywhere) describes the entire cosmic transcendental universe.

If you were to reduce spiritual practice to its simplest form or the lowest common denominator, then all you need is to meditate on OM.

OM Meditation Technique: Sit in a comfortable position with your back straight. Take a deep breath and on your exhale, chant OM stretched (AuuuuuuuuuM). A silence will automatically follow the exhale and then the cycle of inhaling and exhaling with OM repeats.

Krishna, the preceptor of the Gita says

ओं तत् सद् इति निर्देशो ब्रह्मणस् त्रि-विधः स्मृतः ।
ब्राह्मणास् तेन वेदाश् च यज्ञाश् च विहिताः पुरा ॥ २३ ॥
तस्माद् ओं इत्य् उदाहृत्य यज्ञ-दान-तपः-क्रियाः ।
प्रवर्तन्ते विधानोक्ताः सततं ब्रह्म-वादिनाम् ॥ २४ ॥

oṃ tat sad iti nirdeśo brahmaṇas tri-vidhaḥ smṛtaḥ |
brāhmaṇās tena vedāś ca yajñāś ca vihitāḥ purā || 17.23 ||
tasmād oṃ ity udāhṛtya yajña-dāna-tapaḥ-kriyāḥ |
pravartante vidhānoktāḥ satataṃ brahma-vādinām || 17.24 ||

The words “Om Tat Sat” are the representations of the Supreme Absolute Truth, in this eternal manifestation. Any and every action should commence by the uttering of these three syllables, be it the undertaking of a spiritual journey, an act of charity, or to be in a liberated state of peace.