Swami Vivekananda writes in Karma Yoga: The Yoga of Action,

Do you not see how everybody works? Nobody can be altogether at rest; ninety-nine per cent of mankind work like slaves, and the result is misery; it is all selfish work. Work through freedom! Work through love! The word “love” is very difficult to understand; love never comes until there is freedom… If you buy a slave and tie him down in chains and make him work for you, he will work like a drudge, but there will be no love in him. So when we ourselves work for the things of the world as slaves, there can be no love in us, and our work is not true work.