Nirbhao, To Be Fearless; Nirvair, Without Hate, are words from the Mool Mantar, the first composition by Guru Nanak Dev ji. It is a direction for humanity, to lead a life of greatness irrespective of the caste, creed or faith.
Today, The Mool Mantar becomes the be all and end all of the negativity that a person might foster in their being. Nirbhao Nirvair has been engraved in the Sikh Kara as a constant reminder to the wearer, that they are the bearer of a powerful message. A message for all of humanity to live and serve without hate, without fear and without expectations, constantly putting karma out into the universe in keeping with the Gurbani
"With your hands and feet, do all your work, but let your consciousness remain with the Immaculate Lord. ||213||" (SGGS page 1376)