Aum....
Pranava, Om is the Universe“That by which God is effectively praised ” “That which is ever now. ”Pranava means something which pervadeslife or run through Prana or breath. The most sacred symbol in Hinduism, symbolising the unity of Brahman and the Universe. The ‘Aum’ symbol has over 100 meanings - ‘Welcome to God’ being one of them.
The intensity of vibrations produced by the chanting of ‘Om’ is said to affect the entire microcosm and macrocosm. Om or the Pranava
Om represents that power responsible for Creation, Development and Dissolution.This Universe,THE DIVINE HIMSELF
A repesents beggining (Adimatva)U represents progress (Utkarsha)M represents limit or dissolution (Miti) 
A represents the waking state,U represents the dream state,M represents deep-sleep state.
OM....
Man can conquer his beastly nature withthe repetition of Om.