The Spanish Civil War served as a source of inspiration for this song, which speaks of the idealism of the volunteers, who enlisted in the International Brigade to fight against the rebel army that threatened the Republic and democracy in Spain. (1936-1939)
The title of the song comes from a propaganda poster used by the Republican side (see image) to receive international support. The poster featured a photograph of a child killed by the national side during the bombings. The photograph was accompanied by text that read "The "military" practice of the rebels", "If you tolerate this, your children will be next".