Bhagat Singh is credited with giving the slogan Inquilab Zindabad.
He used this slogan to inspire young revolutionaries against British rule. It became especially famous after the 1929 Assembly bomb incident, where Bhagat Singh raised this cry as he was arrested.
Though the words were first written by poet Hasrat Mohani, it was Bhagat Singh who turned it into a symbol of India's freedom movement.