The following is a letter to one of his governors. It speaks volumes about the ways of Divine Rule. It shows how Imam Ali (a) was training the Muslims to behave tolerantly towards other religions, how minority was to be treated and what should those who hold a different creed, expect of a Muslim ruler.
Now, the cultivators 1 (dahaqin, plural of dihqan) of your city have complained of your strictness, hard heartedness, humiliating treatment and harshness. I thought over it and found that since they are unbelievers they cannot be brought near nor kept away or treated severely because of the pledge with them. Behave with them in between strictness and softness and adopt for them a mingling or remoteness and aloofness with nearness and closeness if Allah so wills.