The Guru witnessed the Mughal invasion of India, and saw the horrors inflicted upon the common people by the invaders. Though a pacifist, Guru Nanak did not hesitate to speak up against injustice:
The kings are ravenous beasts, their ministers are dogs.
The Age is a Knife, and the Kings are Butchers
In this dark night of evil, the moon of righteousness is nowhere visible.
Guru Nanak laid forth three basic principles by which every human being should abide:
1. Remember the name of God at all times.
2. Earn an honest living as a householder.
3. Share a portion of your earnings with the less fortunate.