Hamsa Mantra is a powerful Vedic chant. The word hamsa is made of two syllables, ham and sah. Sah means ‘that’ of God, basic reality, ultimate truth, absolute existence or Brahman. ‘Ham’ is a short of aham, which means I. The word hamsa is an inverted form of the famous mantra ‘soham’ which means “I am that, or I am Brahman.”
Bibliography
The Serpent Power (1958) Sir John Wooderoffe, Chennai Ganesh and Co.
An Introduction To Yoga (1951) Annie Besant - Chennai Theosophical Publishing House
Encyclopedia Of Hinduism Volume IV (2011) - page 424 - 425 - IHRF
Mantra is a string of words to be repeated a number of times with concentration of the mind on the meaning of those words. The word om is a short form of the Soham mantra. It is said in Dhyanabinda Upanishad (verse 61), that throughout life the atman present in the human body keeps on repeating Hamsa mantra. The syllable ham is repeated every time the air is exhaled; syllable ‘sah’ is repeated when air is inhaled. Verse 62 declares that the atman repeats Hamsa mantra twenty-one thousand six hundred times in a day and night, i.e. in twenty four hours. This is also called Ajapa Gayatri Mantra. The repetition of this mantra is said to lead to moksha (verse 63). It is said in verse 64 that there is no other mantra or japa similar to this in its efficacy, as there is no other vidya (knowledge) similar to this vidya of Ajapa Gayatri, and nothing else is so full of punya (virtue and merit) as this mantra.
The importance of Hamsa mantra is also described in Brahmavidya Upanishad (verses 21 or 31). It is also mentioned in high terms in Mahavakya Upanishad (verse 5 and 6).
Bibliography
The Serpent Power (1958) Sir John Wooderoffe, Chennai Ganesh and Co.
An Introduction To Yoga (1951) Annie Besant - Chennai Theosophical Publishing House
Encyclopedia Of Hinduism Volume IV (2011) - page 424 - 425 - IHRF