Other [non-Buddhist] paths are either incomplete expressions of the noble eightfold
path or are based on other principles.
For example, they may state that
there is a being who can sidestep the law of kamma and provide for one's
happiness without one's having to master the skills of the noble
eightfold path, or that certain ritual actions or words can provide a
similar shortcut to happiness.
People who follow either of these two
latter beliefs could well feel threatened by outsiders who do not share
their beliefs, for the outsiders are in effect denying the existence of a
shortcut on which the insiders are placing their hopes. This explains
why such people have often been intolerant of outside views.
But because the principle of kamma is a teaching of full personal
responsibility, no one who believes in kamma will feel threatened by
people who teach shortcuts around kamma. Buddhists who have yet to
attain stream-entry may waver in their conviction — as the path can seem
long and arduous, and the results slow in coming — and this is one
reason why they are encouraged not to associate with anyone who rejects
the principle of kamma.
But those who have had their first taste of
Awakening can in no way be persuaded to doubt the principle, for they
have seen that the Deathless can be touched only through a process that
requires the utmost skill in mindfulness and discernment applied to the
processes of one's own mind.
Their attitude toward other teachings is
that of a skilled artisan toward those with lesser skills, or of a woman
who has learned how to extract sesame oil from sesame seeds toward
those who are still trying to extract it from gravel: she will want to
teach them the right way if they are willing to listen, but if they are
unwilling, she will tolerate their ignorance and hope that someday they
will be ready to learn.
~ Thanissaro Bhikkhu "Wings to Awakening"
(formatting is mine)
