The phrase "An army of the people is invincible!" underscores the belief that a military force comprised of the populace is unbeatable. It reflects the idea that when the people unite and fight for a common cause, they possess strength that can overcome any adversity. This notion emphasizes the importance of collective effort and determination in achieving victory, suggesting that popular support is crucial for any successful military endeavor.

This quote, found in the book "Quotations from Chairman Mao Tse-Tung" by Mao Zedong, encapsulates the revolutionary spirit of the era. It promotes the concept of people's warfare, advocating that the true power of an army lies not just in its weaponry but in the passion and commitment of its soldiers. Mao's teachings highlight the vital role of the masses in shaping the course of history through their active participation in struggle and resistance.