Since this discussion has also moved into tolerance to other religions, teachings . . .
One day the Buddha saw a young man worshiping the six directions, a common religious practice at that time. He asked Sigàla why he was doing this and the young man replied that his father, on his death bed, had made him promise to do it and thus continue a family tradition. Although the Buddha had little regard for such practices, he could see that Sigàla’s intentions were good, that he was worshiping the directions out of respect for his father and keeping the promise he had made to him. So rather than criticize or condemn the practice, he asked Sigàla to modify it slightly, to see the people he had relationships with – his parents, children, friends, employees, teachers etc, as equivalent to the directions and to worship them by treating them with kindness, respect and love (Digha Nikaya III. 181).
Upali lived during the time of Buddha and was the follower of another religion and went to the Buddha in order to argue with him and try to convert him. But after talking to the Buddha, he was so impressed that he decided to become a follower of the Buddha. But the Buddha said:
“Make a proper investigation first. Proper investigation is good for a well-known person like yourself.
“Now I am even more pleased and satisfied when the Buddha says to me: 'Make a proper investigation first.' For if members of another religion had secured me as a disciple they would have paraded a banner all around the town saying: 'Upali has joined our religion.' But the Buddha says to me: Make a proper investigation first. Proper investigation is good for a well-known person like yourself”."
(Majjhima Nikaya 2.379)
King Piyadasi, honors both ascetics
and the householders of all religions, and he honors them
with gifts and honors of various kinds.
But Beloved-of-the- Gods, King Piyadasi, does not value gifts and honors as much
as he values this — that there should be growth in the essentials
of all religions.
Growth in essentials can be done in different
ways, but all of them have as their root restraint in speech, that
is, not praising one’s own religion, or condemning the religion
of others without good cause. And if there is cause for criticism,
it should be done in a mild way. But it is better to honor other
religions for this reason. By so doing, one’s own religion benefits,
and so do other religions, while doing otherwise harms one’s
own religion and the religions of others. Whoever praises his
own religion, due to excessive devotion, and condemns others
with the thought “Let me glorify my own religion,” only harms
his own religion. Therefore contact (between religions) is good.
One should listen to and respect the doctrines professed by others.
Beloved-of-the-Gods, King Piyadasi, desires that all should
be well-learned in the good doctrines of other religions.
Those who are content with their own religion should be told
this: Beloved-of-the-Gods, King Piyadasi, does not value gifts
and honors as much as he values that there should be growth in
the essentials of all religions. And to this end many are working
— Dhamma Mahamatras, Mahamatras in charge of the women’s
quarters, officers in charge of outlying areas, and other such
officers. And the fruit of this is that one’s own religion grows
and the Dhamma is illuminated also.
(King Ashoka Edict 12)
Here is a good essay by Bhikkhu Bodhi: http://www.accesstoinsight.org/lib/auth ... ay_24.html
The first extreme is a retreat into fundamentalism, the adoption of an aggressive affirmation of one's own beliefs coupled with a proselytizing zeal toward those who still stand outside the chosen circle of one's co-religionists. While this response to the challenge of diversity has assumed alarming proportions in the folds of the great monotheistic religions, Christianity and Islam, it is not one toward which Buddhism has a ready affinity, for the ethical guidelines of the Dhamma naturally tend to foster an attitude of benign tolerance toward other religions and their followers. Though there is no guarantee against the rise of a militant fundamentalism from within Buddhism's own ranks, the Buddha's teachings can offer no sanctification, not even a remote one, for such a malignant development.
For Buddhists the more alluring alternative is the second extreme. This extreme, which purchases tolerance at the price of integrity, might be called the thesis of spiritual universalism: the view that all the great religions, at their core, espouse essentially the same truth, clothed merely in different modes of expression. Such a thesis could not, of course, be maintained in regard to the formal creeds of the major religions, which differ so widely that it would require a strenuous exercise in word-twisting to bring them into accord.
To the extent that a religion proposes sound ethical principles and can promote to some degree the development of wholesome qualities such as love, generosity, detachment and compassion, it will merit in this respect the approbation of Buddhists. These principles advocated by outside religious systems will also conduce to rebirth in the realms of bliss — the heavens and the divine abodes. Buddhism by no means claims to have unique access to these realms, but holds that the paths that lead to them have been articulated, with varying degrees of clarity, in many of the great spiritual traditions of humanity. While the Buddhist will disagree with the belief structures of other religions to the extent that they deviate from the Buddha's Dhamma, he will respect them to the extent that they enjoin virtues and standards of conduct that promote spiritual development and the harmonious integration of human beings with each other and with the world.