The musical is about French uprisings against the monarchy in the 19th century. Many of the songs have revolutionary themes. "It is the music of the people who will not be slaves again" Likely a reference to the French revolution (late 18th century). The revolution was successful, but after the campaigns of Napoleon, the French were defeated, and the Monarchy was reinstated. So this line is likely comparing being controlled by a monarchy to being a slave. They wish to have another revolution, and overthrow the monarchy again.

Les Miserables takes place during the French Revolution. The song is sung by the revolutionaries who are looking forward to a better future with a new, more egalitarian government.

هل تسمع الناس في الغناء؟ غناء أغنية من الرجال الغاضبين؟ فمن الموسيقى للشعب الذين لن يكونوا عبيدا مرة أخرى! عندما ضرب قلبك أصداء ضرب الطبول هناك حياة على وشك أن تبدأ عندما يأتي غدا ...