Faith: Belief or creed that is used as an orientation in the world and society of a philosophical or religious kind.
Man is a creature of faiths, an ideological ape, a rationalizing animal, and the reason is that human beings are too intelligent not to see the past, the future and its dangers, and many kinds of possible explanations for their experiences, and so have much to fear, not only in this life, but in a life to come that they are promised or threatened with by religious prophets, and have the gift of language and abstract ideas to paint all manner of possibilities for them in fantastic colours, that are very well geared to their emotions, needs and prejudices by systematic wishful thinking and are usually not much influenced by rational thinking, intelligence or scientific method, since these three ways to knowledge are only interesting and useful to a small gifted minority.
Thus, the reason that there are so many human beings who feel proud to belong to some religion or political creed or party is that so many human beings are natural born followers without good or great intelligence, and with little true originality or courage of their own. (Since most of this is not a matter of personal choice, and since no one wished himself or herself on the world, all of this is excusable and understandable, even if it also is the foundation of extra-ordinarily much evil in human history.)
As a rule, a faith is a simplified version of a political ideology or a religion, and plays the same role for the faithful as these: It provides ideas about what the world is (a metaphysics) and what it should be (an ethics), and besides it gives coherence, agreement, and possibilities of cooperation for the faithful, whether these are political, such as Marxists or Liberals or Conservatives, or religious, whether Christian, Mohammedan, Buddhistic or Hindu.
Usually, the truly faithful are the none-too-intelligent, who have much to fear and little power of independent individual thought, and who have therefore a strong inclination towards conformism, followership, and the belief in authorities and leaders, and who are, therefore, in times of crisis also easily moved to fanaticism.
Also, by far the best guess about leaders of the faithful is that they do not really believe the faith in which they lead, and certainly not in the way they propound the faith, but are in it for the money, the status, the power or other privileges. (See: Clergy, Priests)