ॐ पूर्णमदः पूर्णमिदं | Om Purnamadah Purnamidam | Vedic Chants | Shanti Mantra

This chant is a Shanti mantra (peace invocation) and appears primarily in Isha Upanishad (Ishopanishad) or many times called Ishavasya Upanishad (one of the primeval Upanishad).
This mantra is commonly chanted as a prayer before the study of Upanishad begins.
Practicing Vedic mantras systematically, diligently, and with total concentration will lead you to a state of complete healing energy, and this will allow your physical, mental, and energetically body to regain its natural state.

To truly understand the transformative power of the Vedic mantras, we need to realize that any form of sound in the creation is vibrational energy.

ॐ पूर्णमदः पूर्णमिदं पूर्णात्पूर्णमुदच्यते ।
पूर्णस्य पूर्णमादाय पूर्णमेवावशिष्यते ॥
ॐ शान्तिः शान्तिः शान्तिः ॥
Om Puurnnam-Adah Puurnnam-Idam Puurnnaat-Puurnnam-Udacyate |
Puurnnasya Puurnnam-Aadaaya Puurnnam-Eva-Avashissyate ||
Om Shaantih Shaantih Shaantih ||

Meaning:
Om! That is infinite, and this (universe) is infinite.
The infinite proceeds from the infinite.
(Then) taking the infinitude of the infinite (universe),
It remains as the infinite alone.
Aum! Peace! Peace! Peace!