What do you think is the most important idea put forth by judaism, christianity or islam to western society and why?
It's important to not lose sight of the fact that these are the world's three Abrahamic religions and the world's only monotheistic religions. The most important idea put forth by all three religions is the belief in a single, all-powerful diety.
As a Christian, I have to say that the concept of salvation by grace is the most important idea that is put forth by Christianity. The idea that a loving Father would sacrifice his only Son in order to expiate the sins of all humankind just overwhelms me with gratitude. That one's stature in society, one's contributions to the church's coffers, and one's list of good works are all nothing in comparison to the beautiful gift of everlasting life given freely by Christ's willing sacrifice is truly a revolutionary idea.
I certainly agree that historically, the idea of there being one God is the key which began with Judaism and was later built on by Christianity and then Islam.
However, the most powerful concept in terms of today is the idea of truly loving one another -- getting rid of the whole concept of me first, the ends justify the means, money rules, etc.
Here's a great quote from a friend's bumper sticker:
When the power of love is stronger than the love of power, then we will see real peace.
I also have great sympathy for the point raised by #6, which is that the true path of each of these religions is to become one with God and in harmony with the universe. Whatever your religion, that is the one true meaning in my opinion. I believe strongly that all this warring stuff -- the Crusades, jihad, etc. -- is antithetical to the true meaning of religion.
Since many of us are in basic agreement, I thought the biblical references might be pertinent here. In regards to Christianity, I also believe the most important idea put forth to Western society was revealed by Jesus himself when he gave his disciples a "new" Commandment in the New Testament: "Love one another as I have loved you" (John 13:34) furthering the concept with "whatsoever you do to the least of my people, that you do unto me" (Matthew 25:40). However, a concept shared by the three faiths you mention is also an important idea which is, "I am the Lord your God, you shall have no other gods besides Me" (Exodus 20:2-3). This is the first Commandment presented through Judaism, and one that was not negated, but confirmed, by Jesus' "new" commandment.
Put simply as two important concepts: others before self and only one God.
I can only speak with real experience about Christianity. I would say that its most important idea is that the "US" is more important than the "I." Put another way, it says that "YOU" are as important as "I." Parables such as "The Prodigal Son" and "The Good Samaritan" lay out a clear plan about how we could all live together better. Sadly, as someone once said, the problem isn't that Christianity has been tried and failed, but that it has never been seriously tried at all.
(I suspect that the contributions of Judiasm and Islam would the same, but I am not as familiar with these religions and I'll leave answering that up to an expert.)
I think that the common thread that runs in each of these three major religious ideologies is the concept of hospitality or treating strangers with kindness.
The idea that Abraham entertained angels by feeding them with bread baked on a flat stone is an interesting one. It is said that it is good to be kind to strangers as one might be entertaining angels unawares as Abraham had done.
Islam uses the sacrifices during Ramadan to feed the poor. Mecca and the area was home to many trade caravans long before the religious affiliation with Islam was associated. Hospitality is good for business and commerce.
And Christians use alms and charities to feed the homeless, abused and elderly partly in response to the directive of Paul who said "care for the widows and orphans" when writing a letter to Timothy.
As a Jewish person who knows a little something about Christianity and Islam, I would have to choose the idea of worshiping one God as the most powerful idea each of these religions has either contributed or built upon. Before we had one God, people worshiped many gods, leading to competition, corruption, and idolatry. Once the idea of one God began to spread among mankind, an idea attributed to Judaism, the two subsequent religions, Christianity and Islam, chose different ways of seeing and worshiping God, but kept the essential idea because it was such a powerful one. These three religions are a powerful lesson, which is that there are many ways of perceiving and worshiping God with sincere and deeply held beliefs. If there is only one God, then we are all a community and there should be no such thing as a stranger.
In all three cases, we see the concepts of personal accountability, responsibility, and obligation to a higher cause or power.
All three religions believe in a supreme being, or a form of God. All three believe that common courtesy and helping others are positive things, and all three give some sense of a moral compass by which to live.
By instilling a sense of duty to God and others, all three religions are enhancing our western culture as we know it. The charity and kindness displayed by each (in their non-radical forms) are an asset to our world as we know it.
Religions are memes.
There is general agreement among cognitive scientists that a propensity to follow religions evolved early in human history. However, there is disagreement on the exact mechanisms that drove the evolution of the religious mind. There are two schools of thought. One is that religion evolved due to natural selection by directly conferring some sort of evolutionary advantage.
The other hypothesis posits that religion is an evolutionary byproduct, a neurological accident. Stephen Gould believed that religion was a byproduct of other psychological mechanisms that evolved by conferring evolutionary benefits, but that religion itself confers no particular benefit on its followers.
Religious memes are particularly strong memes. They pass from parent to child and across a single generation through proselytism. Most will hold their parent's religion throughout their life. Many religions feature adversarial elements, punishing apostasy or demonizing infidels. Believers view the conversion of non-believers both as a religious duty and as an act of altruism. The promise of eternity in heaven to believers or hell to non-believers provides a strong incentive to accept and retain Christian faith.
In an ideal world, the point of any religion is to nourish the social side of human nature. All religions divide the world into good and evil, right and wrong, do's and don'ts. And the purpose of religion is to reward good behaviour with feelings of approval, support, security and well-being and an ultimate promise of a happy-ever-afterlife.
We all experience moments in our lives that we could call 'spiritual' or 'divine'. Love, beauty, truth, happiness, one-ness and so on. These moments are wonderful, but they are fleeting and easily lost. Religion should help us focus on this spiritual side of our humanity and encourage us to develop our emotional intelligence and empathy, sympathy, self-awareness, etc.
The central message of the three Abrahamic religions, when you have stripped away all the voodoo and tribal stories and proto-legal systems is very very simple social contract...
Love thy neighbour.
(because this instruction contains a simple appeal to reason; the unvoiced quid pro quo that you, as your neighbour's neighbour, will then also be loved.)
The most important idea of religion is to make me realise that killing you and stealing your things is ultimately not in anyone's long-term best interests, not even mine.
"You shall have no other gods before me" pretty much sums up a me first attitude. I think there are too many contradictory scenes in most religious works, that while some may say "love one another," in another passage directly following it, that might not be necessarily so.
In light of the sense we get from reading religious works and finding individual advice, the most important is still one god, and no others (before.)
I would say that the greatest contribution of the three religions is that they postulate that you can only have one god. By having one god, the religions try to oust pagan beliefs, and so many other belief systems that have many gods.
As for personal beliefs in what they promulgate, it might be hard to do that when so many things can be twisted and bent so that one can almost see anything they want in the religious books of the three religions.
I have not read much about these three religion, but the culture of the country where I live, that is India, teaches that different religions are but different paths to the same goal. I believe, all these three religion plus the ancient Indian philosophy, speak of one common goal for all human beings - that is salvation, or becoming one with Ultimate God. Various religions do talk about something like hell and heaven, but to reach heaven is not the ultimate goal.
Another common feature of all major religios of the world is that they guide people towards behavior that combines the common good of the society with individual.