user-1: Namo Buddhaya!
My neighbor is a hardcore Christian & is a very nice man, the only thing is that he goes outside every once & a while with a water gun & kills insects (and even shoots rabbits with the gun). He also really pushes his religion on others and expects people to be Christians, otherwise, they will suffer eternally in Hell. This makes me concerned about the amount of bad Kamma he may be accumulating from his actions, thoughts, & speech.
I had 3 questions:

Is it skillful to not intervene in his acts of killing, knowing he will not understand?
What is an appropriate response to him asking if I "love Jesus only" or if I'm a "good Chrisitan"?
Should I not worry about un-deluding his mind to help him understand the Dhamma?

Metta to all!

user295: 

Is it skillful to not intervene in his acts of killing, knowing he will not understand?


You should tactfully intervene. One should point out animals also feel pain and one should not do to animals what one does not like done to oneself.


What is an appropriate response to him asking if I "love Jesus only" or if I'm a "good Chrisitan"?


You can point out it is good to love Jesus. Also to be a better Christian one can practice:

morality
mastery over the mind
wisdom

Whatever religion or faith system one can practice the above 3 trainings.
You can then direct him to a course which teacher these:

http://www.dhamma.org/en/index
http://www.internationalmeditationcentre.org/global/index.html



Should I not worry about un-deluding his mind to help him understand the Dhamma?


You should not worry. One should just try and accept whatever outcome.

user16632: I empathize with you, having grown up around such people. 
My advice would be to show this neighbor the same love and compassion you feel towards the rabbits and others. You may think of him as just another creature, acting out his natural tendencies, much like a tiger or alligator. Reflect on his positive aspects. Be mindful of your own reactions, feeling, or aversion toward him or his actions, and let go of that which you can't control.
Teach the Dhamma through your actions, they speak louder than words. Be compassionate towards the creatures under your care, and therefore be a friend to him. Change comes from within, so trying to teach at him or argue against his beliefs will never bear fruit. Show kindness, wisdom, positivity, and equanimity through your actions and the visible benefits of the Dhamma will become apparent to those with eyes to see and ears to hear.

user8157: The suttas say to teach Dhamma only to those who ask for it. Therefore, you are forbidden to preach Dhamma to your neighbour (unless he wishes you do). 

Etadaggaṃ peyyavajjānaṃ yadidaṃ atthikassa ohitasotassa punappunaṃ
  dhammaṃ deseti.
And this is the best of friendly speech: to teach again and again
  Dhamma to those who wish for it and who listen attentively.
AN 9.5

As for Christianity, Jesus taught people go to 'heaven' & 'hell' as a result of their actions rather than as a result of superficial faith or allegiance. Refer to Parable of the Good Samaritan. 

-1: <p>Namo Buddhaya!</p>

<p>My neighbor is a hardcore Christian &amp; is a very nice man, the only thing is that he goes outside every once &amp; a while with a water gun &amp; kills insects (and even shoots rabbits with the gun). He also really pushes his religion on others and expects people to be Christians, otherwise, they will suffer eternally in Hell. This makes me concerned about the amount of bad Kamma he may be accumulating from his actions, thoughts, &amp; speech.</p>

<p>I had 3 questions:</p>

<ul>
<li>Is it skillful to not intervene in his acts of killing, knowing he will not understand?</li>
<li>What is an appropriate response to him asking if I "love Jesus only" or if I'm a "good Chrisitan"?</li>
<li>Should I not worry about un-deluding his mind to help him understand the Dhamma?</li>
</ul>

<p>Metta to all!</p>
 295: <blockquote>
  <ul>
  <li><strong>Is it skillful to not intervene in his acts of killing, knowing he will not understand?</strong></li>
  </ul>
</blockquote>

<p>You should tactfully intervene. One should point out animals also feel pain and one should not do to animals what one does not like done to oneself.</p>

<blockquote>
  <ul>
  <li><strong>What is an appropriate response to him asking if I "love Jesus only" or if I'm a "good Chrisitan"?</strong></li>
  </ul>
</blockquote>

<p>You can point out it is good to love Jesus. Also to be a better Christian one can practice:</p>

<ul>
<li>morality</li>
<li>mastery over the mind</li>
<li>wisdom</li>
</ul>

<p>Whatever religion or faith system one can practice the above <a href="https://en.wikipedia.org/wiki/Threefold_Training" rel="nofollow noreferrer">3 trainings</a>.</p>

<p>You can then direct him to a course which teacher these:</p>

<ul>
<li><a href="http://www.dhamma.org/en/index" rel="nofollow noreferrer">http://www.dhamma.org/en/index</a></li>
<li><a href="http://www.internationalmeditationcentre.org/global/index.html" rel="nofollow noreferrer">http://www.internationalmeditationcentre.org/global/index.html</a></li>
</ul>

<blockquote>
  <ul>
  <li><strong>Should I not worry about un-deluding his mind to help him understand the Dhamma?</strong></li>
  </ul>
</blockquote>

<p>You should not worry. One should just try and accept whatever outcome.</p>
 16632: <p>I empathize with you, having grown up around such people. </p>

<p>My advice would be to show this neighbor the same love and compassion you feel towards the rabbits and others. You may think of him as just another creature, acting out his natural tendencies, much like a tiger or alligator. Reflect on his positive aspects. Be mindful of your own reactions, feeling, or aversion toward him or his actions, and let go of that which you can't control.</p>

<p>Teach the Dhamma through your actions, they speak louder than words. Be compassionate towards the creatures under your care, and therefore be a friend to him. Change comes from within, so trying to teach at him or argue against his beliefs will never bear fruit. Show kindness, wisdom, positivity, and equanimity through your actions and the visible benefits of the Dhamma will become apparent to those with eyes to see and ears to hear.</p>
 8157: <p>The suttas say to teach Dhamma only to those who ask for it. Therefore, you are forbidden to preach Dhamma to your neighbour (unless he wishes you do). </p>

<blockquote>
  <p>Etadaggaṃ peyyavajjānaṃ yadidaṃ atthikassa ohitasotassa punappunaṃ
  dhammaṃ deseti.</p>
  
  <p>And this is the best of friendly speech: to teach again and again
  Dhamma to those who wish for it and who listen attentively.</p>
  
  <p><a href="https://www.accesstoinsight.org/lib/authors/nyanaponika/wheel238.html" rel="nofollow noreferrer">AN 9.5</a></p>
</blockquote>

<p>As for Christianity, Jesus taught people go to 'heaven' &amp; 'hell' as a result of their actions rather than as a result of superficial faith or allegiance. Refer to <a href="https://en.wikipedia.org/wiki/Parable_of_the_Good_Samaritan" rel="nofollow noreferrer">Parable of the Good Samaritan</a>. </p>
