Doing something bad with a good intention

Question

I recently studied the story of Hannah in school. I learned that Penninah would make fun of Hannah for not having children so she could reproach herself and pray deeply to G-d. Penninah was actually doing this with a good intention, believing G-d would see her agony and make her conceive. But Penninah was punished with the death of her children because one can't antagonize somebody even if it's for a good reason.

But I've also learned that the intention counts. I've learned that if you think you're doing a mitzvah for G-d with all your heart and it results you're not doing it well, it still counts (although maybe not in the same level).

This may sound arguable and wrong but I've also discussed with friends some philosophical questions regarding this subject. Like "If a terrorist really believes he is doing the right thing and he is doing it for G-d, what happens to him in the afterlife? How is he judged?"

So back to the point, does G-d care about the intention?

Answer 1

this was posed to Rabbi Zev Leff, a well known halachic authority in Israel:

The suicide bombing Moslems, who do their dastardly deed "in the name of G-d", truly believe that what they are doing is right. They feel like they are being mekadesh shem shamayim (Sanctifying G-d's name) by murdering as many Jews as they can while making the ultimate self sacrifice by giving up their lives, and thereby sending themselves straight to Heaven. Does G-d when he judges them, take into consideration the fact that they all seem to be doing what they do leshaim shamayim (In the name of G-d)?

answer: Rabbi Weintraub answers they are not doing it for God's sake they have incentives of all sorts of pleasures they are going to get... see there for more

http://www.rabbileff.net/shiurim/answers/0000-0249/0018.mp3

as to the general question of whether intention is important, the chovos halevavos discusses this in the intro:

I found in the Torah regarding one who kills someone unintentionally, no capital punishment is incurred. Likewise, one who performs a sin unintentionally which if intentional would incur either capital punishment or the penalty of Karet (excision), the person had only to bring for them a sin-offering or an asham offering. All this is a clear proof that the essential condition of liability for punishment is the association of mind and body in a forbidden act, the mind by its intention, and the body by its movement. So too our wise men said (regarding good deeds): "whoever performs a religious duty but did not intend to do it for the sake of G-d - he will not receive reward for it." And since the hinge and pillar of all deeds rests on the foundation of intention and hidden sentiment of the heart, a system of the duties of the heart should precede, by nature, a system of the duties of the limbs.

the talmud also discusses a sin with good intentions regarding Yael. forgot where.

Answer 2

I heard this from Rabbi Eli Mansour: Pnina was a tzadeket a wife of a tzadik! she was doing this so Hanah would pray with more kavanah and tears, which two conditions known to be accepted by hashem in a prayer faster. That being said, she was punished anyway because out of her good intentions, she secretly came to enjoy it, hence she lost all her children. So everytime we think we can do something bad with good intentions we should think that hashem rewards midah kneged midah, is it worth it? That's up to each person to answer to hashem!