Originally posted by sinweiy:
recently, i heard from Ven Tian Yin who was answering about
Bodhisattva precepts, that non-intentional action also have
non-intentional karma. He cited a case in the sutra, about this
Bhikshu(?) who non-intentionally place a glass of water onto an
ant(?) and crushed it. in the next life, the Bhikshu was meditating
under a cliff, a boar came and was trying to scratch its teeth on a
huge rock on the cliff. the rock fell and crushed the Bhikshu. the
boar was the incarnation of the ant and had also no intention of
killing.
Ah yes... thats right... when a person is not careful with his
things, doesnt mean he wont commit karma!
First we must understand in terms of 5 skhandas. There is no doer
of deed, and there is nobody experiencing the effect. It is made up
of 5 skhandas, it is the Volition doing the deed.
When we speak of "intentions"/"volition", we must know that
volition is part of every sentient being (5 Skhandas), so even
though "he" does not know what he has done that, "his" volition of
doing shall create the karma. Only an enlightened person can
transcend that, that is Non-volition. But non-volition is not the
same as not knowing because not careful. Non-volition must be
understood in terms of Prajna/Wisdom. Without prajna, a person
cannot attain non-volition. That is why an enlightened person no
longer creates karma. Thus learnt from Thusness.
karma of killing is like this. if person A kill person B, person
B will feel that he would want to kill back person A. to erase the
killing karma, person B have to Forgive person A, hence the action
of killing have to stop in either of the person.
when Buddha was a bodhisattva, out of compassion and wisdom, He
killed the killer who was about to kill all the people on the boat.
the bodhisattva actually took on the karma of reborning into hell
for the killer. even if the action of killing is out of compassion,
the bodhisattva(who have not reached a level of Tenth Bhumi) will
still have to watch their Actions and intention.
/\[/b]
Yes! A Bodhisattva does willingly commit "sins" for sentient
beings. My dharma teacher herself also said, for example, if the
dharma centre is full of mosquitoes/etc, she might take up the
karma for the sake of spreading dharma for us, she might call the
pest control. 
But I think I don't
have wisdom and I dare not take up karma for sake of others...