Most Buddhists will tell you Buddhism is not a religion, and that it certainly is not a faith. Many Hindus say that Hinduism is not a religion, and that the word “faith” comes more from an Abrahamic context. I don’t pretend to understand Buddhism as well as I might, so I will not address it too deeply here. As for Hindus, one of the reasons “Hinduism is not a religion” is because it is not unified under one umbrella, i.e., it is not one religion.
But it is also “not a religion” because the proper way to refer to Hinduism is “Sanatana Dharma” which, even though it is often translated as “The Eternal Religion” it is really just a way of conduct. It is a belief in oneness, that all comes from the same source. I prefer to think of my personal dharma as such, instead of “Hinduism” which can mean a million different things. It is kind of like asking ten people in the dark to grab onto an elephant and then tell you what an elephant looks like. You are going to get ten very different answers depending on which part of the creature the person has touched.
Many will say that through study of ancient wisdom (jnana yoga) and through meditation ourselves, we can see that we are eternal. “We don’t need to believe, because we know” is how many would put it.
But I think this requires a belief, a faith on a grand scale. When we say “we don’t have to believe, because we know” we are referring to the knowledge of the eternal Self we glean through meditation. Some call this the “God, present in all of us” or the “Guru present in all.” The faith comes in having the absolute certainty that one’s knowledge is not mistaken, certainty that one is not in delusion. So one is still living by a certain degree of “faith” in the ever-present, eternal Self, or God that I mentioned above.
Do I “know” this is not the one lifetime I have in order to do whatever it is that I have to do to remove myself from the bondage of the material world? No I do not. I do not doubt it based on understandings I now possess from wisdom carried down through the ages, and through my own meditations. And other spiritual paths have not proven to present as strong a case to me. But, contradictory as it may sound, I still cannot say I “know” it. Hence, faith.