user8218: According to Buddhist teachings, is it possible to continue to reborn and suffer for all eternity?
Suppose if a being never attained any merit, never was able to work through its old karma. Would it be possible for that being to never escape suffering?
I have heard some people say:

No, nobody can be reborn and suffer forever. For an extremely long time, maybe, but not forever.

I mean, forever is really an astounding concept. Even if you take billions of trillions of gazillions of births it's still nothing compared to forever.
If it's not possible to be reborn forever, then it implies that all beings are eventually destined for Enlightenment. Some may have an insanely long way to go, but if they're not gonna be reborn forever, then they have to eventually attain Enlightenment?
Do some beings continue to be reborn and suffer forever, or are all beings destined to attain Enlightenment eventually?
I prefer answers that give sources and all that. But some nice reasoning is also welcome.

user2265: First, if I may, I will correct one misunderstanding:
Enlightenment = free from rebirth =/= not no MORE rebirth... 
Enlightenment means one will not be bounded on the wheel of destiny--rather one will be able to help others freely. Thus, do not equate Enlightenment with totally never being born. It's beyond born and unborn.
To answer your question: The latter is correct: all beings are destined to attain Enlightenment eventually. The Mahayana sutras state how people will all be saved at some time or another, specifically Maitreya Buddha who, when he returns, will deliver "billions" of beings at a time through the universe. (Surangama Sutra)
Here is more info on this Buddha:

Maitreya Bodhisattva is the future buddha of this world who currently
  resides in the Tushita Heaven. A Dictionary of Buddhist Terms and
  Concepts relates the following information about him:
"A bodhisattva predicted to succeed Shakyamuni as a future Buddha.
  Also called Ajita, meaning 'invincible.' Some accounts view him as a
  historical personage who preceded the Buddha in death. He is said to
  have been reborn in the Tushita Heaven where he is now expounding the
  Law to the heavenly beings there. It is said that he will reappear in
  this world 5.670 million years after Shakyamuni's death, attain
  Buddhahood, and save the people in Shakyamuni's stead. For this reason
  he is also sometimes called Miroku Buddha. Belief in Miroku prevailed
  in India around the beginning of the first century A.D., and spread to
  China and Japan. In the fourth century, a monk named Maitreya (c.
  270-350) became famous as a scholar of the Consciousness-Only school,
  and was later identified with this bodhisattva." (pp. 266-7)
Maitreya Bodhisattva is the only bodhisattva who is revered by both
  Theravadin and Mahayana Buddhists (aside from Siddhartha Gautama and
  his past lives as a bodhisattva). His coming is predicted in the Pali
  Canon as well as in the Mahayana Sutras.

Although no one falls on the end of the "forever" spectrum--nonetheless, there are certainly people are closer on the spectrum towards "forever" than others, having lived a very impetuous existence with little consideration for spiritual cultivation or making merit (e.g. chanting a Buddha's name).

user8157: Many people are interested in living forever (eg Christians) because such people do not think living is suffering. Instead, they wish to spend forever with their loved ones. That is why they are not queuing up to practise Buddhism. 
My impression is Buddhists are similar, in that they wish to believe in reincarnation so they can live more lives. That is why most Buddhists are not practising the path, hardcore, but preaching that Buddhists must believe in reincarnation, rebirth, whatever. 
Also, Buddhism does not state making merit ends suffering (SN 12.51) so what is its relevance?
Also, Buddhism does not state all beings are destined for enlightenment (AN 10.95).
Imo, the questions are an extreme & pointless misrepresentation of Buddhism. If the questioner truly believe they were suffering, they would be a monk urgently putting out the suffering, like as if their hair was on fire. 

8218: <p>According to Buddhist teachings, is it possible to continue to reborn and suffer for all eternity?</p>

<p>Suppose if a being never attained any merit, never was able to work through its old karma. Would it be possible for that being to never escape suffering?</p>

<p>I have heard some people say:</p>

<blockquote>
  <p>No, nobody can be reborn and suffer forever. For an extremely long time, maybe, but not <em>forever.</em></p>
</blockquote>

<p>I mean, <em>forever</em> is really an astounding concept. Even if you take billions of trillions of gazillions of births it's still <em>nothing</em> compared to <em>forever</em>.</p>

<p>If it's <em>not</em> possible to be reborn forever, then it implies that all beings are eventually destined for Enlightenment. Some may have an insanely long way to go, but if they're not gonna be reborn forever, then they have to <em>eventually</em> attain Enlightenment?</p>

<p><strong>Do some beings continue to be reborn and suffer forever, or are all beings destined to attain Enlightenment <em>eventually</em>?</strong></p>

<p>I prefer answers that give sources and all that. But some nice reasoning is also welcome.</p>
 2265: <p>First, if I may, I will correct one misunderstanding:
Enlightenment = free from rebirth =/= not no MORE rebirth... </p>

<p>Enlightenment means one will not be bounded on the wheel of destiny--rather one will be able to help others freely. Thus, do not equate Enlightenment with totally never being born. It's beyond born and unborn.</p>

<p>To answer your question: The latter is correct: all beings are destined to attain Enlightenment eventually. The Mahayana sutras state how people will all be saved at some time or another, specifically Maitreya Buddha who, when he returns, will deliver "billions" of beings at a time through the universe. (Surangama Sutra)</p>

<p>Here is more info on this Buddha:</p>

<blockquote>
  <p>Maitreya Bodhisattva is the future buddha of this world who currently
  resides in the Tushita Heaven. A Dictionary of Buddhist Terms and
  Concepts relates the following information about him:</p>
  
  <p>"A bodhisattva predicted to succeed Shakyamuni as a future Buddha.
  Also called Ajita, meaning 'invincible.' Some accounts view him as a
  historical personage who preceded the Buddha in death. He is said to
  have been reborn in the Tushita Heaven where he is now expounding the
  Law to the heavenly beings there. <strong>It is said that he will reappear in
  this world 5.670 million years after Shakyamuni's death, attain
  Buddhahood, and save the people in Shakyamuni's stead.</strong> For this reason
  he is also sometimes called Miroku Buddha. Belief in Miroku prevailed
  in India around the beginning of the first century A.D., and spread to
  China and Japan. In the fourth century, a monk named Maitreya (c.
  270-350) became famous as a scholar of the Consciousness-Only school,
  and was later identified with this bodhisattva." (pp. 266-7)</p>
  
  <p>Maitreya Bodhisattva is the only bodhisattva who is revered by both
  Theravadin and Mahayana Buddhists (aside from Siddhartha Gautama and
  his past lives as a bodhisattva). His coming is predicted in the Pali
  Canon as well as in the Mahayana Sutras.</p>
</blockquote>

<p>Although no one falls on the end of the "forever" spectrum--nonetheless, there are certainly people are closer on the spectrum towards "forever" than others, having lived a very impetuous existence with little consideration for spiritual cultivation or making merit (e.g. chanting a Buddha's name).</p>
 8157: <p>Many people are interested in living forever (eg Christians) because such people do not think living is suffering. Instead, they wish to spend forever with their loved ones. That is why they are not queuing up to practise Buddhism. </p>

<p>My impression is Buddhists are similar, in that they wish to believe in reincarnation so they can live more lives. That is why most Buddhists are not practising the path, hardcore, but preaching that Buddhists must believe in reincarnation, rebirth, whatever. </p>

<p>Also, Buddhism does not state making merit ends suffering (<a href="https://suttacentral.net/en/sn12.51" rel="nofollow">SN 12.51</a>) so what is its relevance?</p>

<p>Also, Buddhism does not state all beings are destined for enlightenment (<a href="http://www.accesstoinsight.org/tipitaka/an/an10/an10.095.than.html" rel="nofollow">AN 10.95</a>).</p>

<p>Imo, the questions are an extreme &amp; pointless misrepresentation of Buddhism. If the questioner truly believe they were suffering, they would be a monk urgently putting out the suffering, like as if their hair was on fire. </p>
