user-1: 
"There are these five inhabitants of the states of deprivation, inhabitants of hell, who are in agony & incurable. Which five? One who has killed his/her mother, one who has killed his/her father, one who has killed an arahant, one who — with a corrupted mind — has caused the blood of a Tathagata to flow, and one who has caused a split in the Sangha. These are the five inhabitants of the states of deprivation, inhabitants of hell, who are in agony & incurable."
AN 5.129

If someone tries to kill an arahant, Buddha or their parents but they don’t get hurt even a little bit, do you still go to hell for “attempting” to kill them? Or is it only incurable if you have succeeded in killing them?

user13709: Since going to hell is a dangerous experiment to conduct, let's focus instead on what we can all verify. In particular, note that action conditioned by ignorance in body, speech or mind cause pleasure and pain to arise.

AN4.171:1.1: “Mendicants, as long as there’s a body, the intention that gives rise to bodily action causes pleasure and pain to arise in oneself.
AN4.171:1.2: As long as there’s a voice, the intention that gives rise to verbal action causes pleasure and pain to arise in oneself.
AN4.171:1.3: As long as there’s a mind, the intention that gives rise to mental action causes pleasure and pain to arise in oneself. But these only apply when conditioned by ignorance.

Killing is a bodily action. Thinking about killing is a mental action. Therefore, just thinking about killing a parent will cause pain and suffering. The difference between killing and thinking about killing a parent is that one cannot unkill a parent. But one can relinquish the thought of killing a parent--even if that thought arises again. And in relinquishing the thought of killing, one can also gradually relinquish ignorance. In this way, thinking about killing a parent is like standing on the edge of hell, leaning forward.
For those who fall into hell there is slim hope.

MN50:21.1: Then Māra Dūsī took possession of a certain boy, picked up a rock, and hit Vidhura on the head, cracking it open.
MN50:21.2: Then Vidhura, with blood pouring from his cracked skull, still followed behind the Buddha Kakusandha.
MN50:21.3: Then the Buddha Kakusandha turned his whole body, the way that elephants do, to look back, saying,
MN50:21.4: ‘This Māra Dūsī knows no bounds.’
MN50:21.5: And with that look Māra Dūsī fell from that place and was reborn in the Great Hell.

Once in Hell, the pain lasts for a very long time as one struggles to emerge from Hell. There is no "parole". There is no doctor nor cure (atekicchā). A sentence to Hell must be served in its entirety.

MN50:23.2: For ten thousand years I roasted in the annex of that Great Hell, experiencing the pain called ‘emergence’.

Eventually, Dūsī served his sentence and was released. And eventually, Dūsī became known as Moggallāna, one of the Gautama Buddha's chief disciples.
So rather than jump into Hell for ten thousand years, perhaps it is better to pull back from the precipice to Hell. Perhaps it is best to restrain and relinquish unskillful thoughts.

-1: <blockquote>
<p>&quot;There are these five inhabitants of the states of deprivation, inhabitants of hell, who are in agony &amp; incurable. Which five? One who has killed his/her mother, one who has killed his/her father, one who has killed an arahant, one who — with a corrupted mind — has caused the blood of a Tathagata to flow, and one who has caused a split in the Sangha. These are the five inhabitants of the states of deprivation, inhabitants of hell, who are in agony &amp; incurable.&quot;</p>
<p><a href="https://www.accesstoinsight.org/tipitaka/an/an05/an05.129.than.html" rel="nofollow noreferrer">AN 5.129</a></p>
</blockquote>
<p>If someone tries to kill an arahant, Buddha or their parents but they don’t get hurt even a little bit, do you still go to hell for “attempting” to kill them? Or is it only incurable if you have succeeded in killing them?</p>
 13709: <p>Since going to hell is a dangerous experiment to conduct, let's focus instead on what we can all verify. In particular, note that action conditioned by ignorance in <em><strong>body, speech or mind</strong></em> cause pleasure and pain to arise.</p>
<blockquote>
<p><a href="https://suttacentral.net/an4.171/en/sujato#an4.171:1.1" rel="nofollow noreferrer">AN4.171:1.1</a>: “Mendicants, as long as there’s a body, the intention that gives rise to bodily action causes pleasure and pain to arise in oneself.<br />
<a href="https://suttacentral.net/an4.171/en/sujato#an4.171:1.2" rel="nofollow noreferrer">AN4.171:1.2</a>: As long as there’s a voice, the intention that gives rise to verbal action causes pleasure and pain to arise in oneself.<br />
<a href="https://suttacentral.net/an4.171/en/sujato#an4.171:1.3" rel="nofollow noreferrer">AN4.171:1.3</a>: As long as there’s a mind, the intention that gives rise to mental action causes pleasure and pain to arise in oneself. But these only apply when conditioned by ignorance.</p>
</blockquote>
<p>Killing is a bodily action. Thinking about killing is a mental action. Therefore, just thinking about killing a parent will cause pain and suffering. The difference between killing and thinking about killing a parent is that one cannot unkill a parent. But one can relinquish the thought of killing a parent--even if that thought arises again. And in relinquishing the thought of killing, one can also gradually relinquish ignorance. In this way, thinking about killing a parent is like standing on the edge of hell, leaning forward.</p>
<p>For those who fall into hell there is slim hope.</p>
<blockquote>
<p><a href="https://suttacentral.net/mn50/en/sujato#mn50:21.1" rel="nofollow noreferrer">MN50:21.1</a>: Then Māra Dūsī took possession of a certain boy, picked up a rock, and hit Vidhura on the head, cracking it open.<br />
<a href="https://suttacentral.net/mn50/en/sujato#mn50:21.2" rel="nofollow noreferrer">MN50:21.2</a>: Then Vidhura, with blood pouring from his cracked skull, still followed behind the Buddha Kakusandha.<br />
<a href="https://suttacentral.net/mn50/en/sujato#mn50:21.3" rel="nofollow noreferrer">MN50:21.3</a>: Then the Buddha Kakusandha turned his whole body, the way that elephants do, to look back, saying,<br />
<a href="https://suttacentral.net/mn50/en/sujato#mn50:21.4" rel="nofollow noreferrer">MN50:21.4</a>: ‘This Māra Dūsī knows no bounds.’<br />
<a href="https://suttacentral.net/mn50/en/sujato#mn50:21.5" rel="nofollow noreferrer">MN50:21.5</a>: And with that look Māra Dūsī fell from that place and was reborn in the Great Hell.</p>
</blockquote>
<p>Once in Hell, the pain lasts for a very long time as one struggles to emerge from Hell. There is no &quot;parole&quot;. There is no doctor nor cure (<em>atekicchā</em>). A sentence to Hell must be served in its entirety.</p>
<blockquote>
<p><a href="https://suttacentral.net/mn50/en/sujato#mn50:23.2" rel="nofollow noreferrer">MN50:23.2</a>: For ten thousand years I roasted in the annex of that Great Hell, experiencing the pain called ‘emergence’.</p>
</blockquote>
<p>Eventually, Dūsī served his sentence and was released. And eventually, Dūsī became known as Moggallāna, one of the Gautama Buddha's chief disciples.</p>
<p>So rather than jump into Hell for ten thousand years, perhaps it is better to pull back from the precipice to Hell. Perhaps it is best to restrain and relinquish unskillful thoughts.</p>
