Faith is one of the foundation of the bodhisatva ideal. What does it means to have faith in buddhism? It's interesting to compare for instance with the christians. For the christians, have faith means believe in God or the Christ. So here we see the difference with buddhism. Because faith for christians is connected with an external power, a supranatural power. Does the word faith can apply in this way for buddhism? Of course not, so it means that faith is not perceived in the same way according different religious. In buddhism, we are not rely on supranatural power or external power because we are our own master and the Buddha gave us a teaching. So, in this case faith is something that supply energy, joy, enthusiasm in practice. For instance when we read a book of Gampopa and the qualities of the Buddha and the benefit of practice the dharma, we cannot ignore faith growing in us. In this way, we are not talking about blind faith but faith should be perceived as confidence and a positive attitude of mind who understand that the buddha nature is within us and we can become a better people. But faith in what? As we saw above, for christians they have faith in God and the Christ, but here I means in buddhism, it means to have faith in the triple gem, the Buddha, the dharma and the sangha. So we see that faith could have a different meaning according religious area, it's an interesting word because it give us a clear picture about what is buddhism and what is not. Mainly, there is no external power in buddhism, anyone can become a buddha because of the buddha nature.
Joseph Campbell on faith
FROM THE POWER OF MYTH, an interview by Bill Moyers with noted mythologist Joseph Campbell
CAMPBELL: A couple of years ago, I had a very amusing experience. I was in the New
York Athletic Club swimming pool, where I was introduced to a priest who was a professor at
one of our Catholic universities. So after I had had my swim, I came and sat in a lounging chair
in what we call the "horizontal athlete" position, and the priest, who was beside me, asked, "Now,
Mr. Campbell, are you a priest?"
I answered, "No, Father."
He asked, "Are you a Catholic?"
I answered, "I was, Father."
Then he asked -- and I think it interesting that he phrased the question in this way -- "Do
you believe in a personal god?"
"No, Father," I said.
And he replied, "Well, I suppose there is no way to prove by logic the existence of a
personal god."
"If there were, Father," said I, "what then would be the value of faith?"
"Well, Mr. Campbell," said the priest quickly, "it's nice to have met you." And he was off.
I felt I had executed a jujitsu throw.
But that was an illuminating conversation to me. The fact that a Catholic father had asked,
"Do you believe in a personal god?" meant to me that he also recognized the possibility of an
impersonal god, namely, a transcendent ground or energy in itself. The idea of Buddha
consciousness is of an immanent, luminous consciousness that informs all things and all lives.
We unthinkingly live by fragments of that consciousness, fragments of that energy. But the
religious way of life is to live not in terms of the self-interested intentions of this particular body
at this particular time but in terms of the insight of that larger consciousness.
There is an important passage in the recently discovered Gnostic Gospel According to St.
Thomas: " 'When will the kingdom come?' Christ's disciples ask." In Mark 13, I think it is, we
read that the end of the world is about to come. That is to say, a mythological image -- that of the
end of the world -- is there taken as predicting an actual, physical, historical fact to be. But in
Thomas' version, Jesus replies: "The kingdom of the Father will not come by expectation. The
kingdom of the Father is spread upon the earth and men do not see it" -- so I look at you now in
that sense, and the radiance of the presence of the divine is known to me through you.
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FWIW
the meaning of faith
As you rightly said, the faith (sraddha) is necessary in the long way of the bodhisattva to attain enlightenment, “faith should be perceived as confidence and a positive attitude of mind who understand that the Buddha nature is within us”.
Firstly we must have faith in the triple gem, Buddha, dharma and sangha. Then, we must have faith in the basic Buddhist doctrines as karma’s law, rebirth, the four noble truths and so forth. Finally, we must have faith in the teacher and his teachings that guide us to the enlightenment.
When we have faith in Buddhism, we begin taking refuge in the triple gem. According to Peter Santina, We also take refuge by fear and compassion. We take refuge by fear because all of us have fear of suffering. The triple gem protects us in the way to enlightenment.
In relation to your comment, it is important to note that the Christianity and Buddhism are really different in doctrine, theology, ontology, cosmology, etc. But when we talk about faith, these both tradition are closer. The faith is important in all religious tradition.
The key question that we can ask: Which is the difference between Therevada, Mahayana and Vajrayana in relation to faith. Has a disciple of Theravada the same faith of those follow the cult to Amitabha? I think that there is different levels of faith in Buddhism.