user11541: It is said that Virtue is the ultimate weapon. It is also said that virtue automatically leads to enlightenment without any volition or desire to achieve enlightenment. 
Therefore I want to develop 'heightened' virtue but I am unable to find any sutta which explains what constitutes Virtue.
In the following quote from AN 3.90 training for heightened virtue is mentioned:

“And what is the training in heightened virtue? There is the case
  where a monk is virtuous. He dwells restrained in accordance with the
  Patimokkha, consummate in his behavior & sphere of activity. He trains
  himself, having undertaken the training rules, seeing danger in the
  slightest fault. This is called the training in heightened virtue.

My questions are :
1. What constitutes virtue ?(Any reference to Suttas would be great.If there are any books giving short summary of Patimokkha in English then that would also be great.)
2. How to train myself in virtue ? (Are there any training books available?)

user254: The Patimokkha is one of the books of the Vinaya, i.e. the rules or code of conduct for monks.
There are English-language translations of (introductions to) the Vinaya here, for example The Patimokkha Rules Translated & Explained by by Thanissaro Bhikkhu.
Dozens of suttas (e.g. SN 56.9) use the word dhammavinaya, translated as teaching and training and/or Dhamma and discipline.
You might like to read the original version of this dictionary entry on the Buddhavacana web site -- it contains hyperlinks to to parts of the various suttas which it references:

adhisīlasikkhā: [adhi+sīla+sikkhā]
training in higher virtue. A definition is given by the Buddha at AN 3.90. It consists of a thorough undertaking of the Pātimokkha's rules.

Adhi·sīla·sikkhā is one of the three sikkhās, together with adhi·citta·sikkhā and adhi·paññā·sikkhā. It is said of these three trainings at AN 3.82 that they are 'ascetic tasks of an ascetic' (samaṇassa samaṇa·karaṇīyāni), at AN 3.93 that they are 'urgent tasks of a bhikkhu' (bhikkhussa accāyikāni karaṇīyāni), and at AN 6.30 that they constitute the 'supreme training' (anuttariyaṃ sikkhā) for the purification of beings, etc. (formula in the style of the Mahāsatipaṭṭhāna Sutta)
They can even replace the Pātimokkha, in some cases (AN 3.85).
However, adhi·sīla·sikkhā is not only for bhikkhus, since it should also be undertaken by upāsakas, as they meet with their success (sampadā) or their prosperity (sambhava), lest it is their their failure (vipatti) as in AN 7.30, their decline (parihāna) as in AN 7.29, or their ruin (parābhava) as in AN 7.31.


AN 7.29 through AN 7.31 says that lay followers (upāsakas) too should practice "higher virtue", but don't define it.
I suspect that "higher" virtue means more than the five precepts.
Maybe in AN 3.85 it's used instead of a detailed set of rules and definitions, and is used with "heightened discernment" (i.e. when you discern what's what, whether something is virtuous and skilful): in summary, "abandon the three poisons, don't do anything unskillful or engage in any evil".

user471: Virtue or sila at the very minimum is the five precepts. Further practice of virtue is by the eight precepts, ten precepts, Right Livelihood, Right Speech and Right Action.
Further information can be found in AccessToInsight's virtue (sila) page, including sutta verses.
To practice virtue (sila), the first step is to vow to undertake the training of the five precepts, and then practice them with heedfulness (appamada).
The second step is to adopt this thinking from AN 5.57: 

“And for the sake of what benefit should a woman or a man, a
  householder or one gone forth, often reflect thus: ‘I am the owner of
  my kamma, the heir of my kamma; I have kamma as my origin, kamma as my
  relative, kamma as my resort; I will be the heir of whatever kamma,
  good or bad, that I do’? People engage in misconduct by body, speech,
  and mind. But when one often reflects upon this theme, such misconduct
  is either completely abandoned or diminished. It is for the sake of
  this benefit that a woman or a man, a householder or one gone forth,
  should often reflect thus: ‘I am the owner of my kamma, the heir of my
  kamma; I have kamma as my origin, kamma as my relative, kamma as my
  resort; I will be the heir of whatever kamma, good or bad, that I do.’

The third step is to understand more deeply from the Dhamma on Right Livelihood, Right Speech and Right Action, and practise them with heedfulness (appamada).

11541: <p>It is said that Virtue is the <a href="https://suttacentral.net/thag12.1/en/sujato-walton" rel="nofollow noreferrer">ultimate weapon</a>. It is also said that virtue automatically leads to enlightenment without any volition or <a href="https://suttacentral.net/an10.2/en/bodhi" rel="nofollow noreferrer">desire to achieve enlightenment</a>. 
Therefore I want to develop 'heightened' virtue but I am unable to find any sutta which explains what constitutes Virtue.</p>

<p>In the following quote from <a href="https://suttacentral.net/an3.90/en/thanissaro" rel="nofollow noreferrer">AN 3.90</a> training for heightened virtue is mentioned:</p>

<blockquote>
  <p>“And what is the training in heightened virtue? There is the case
  where a monk is virtuous. He dwells restrained in accordance with the
  Patimokkha, consummate in his behavior &amp; sphere of activity. He trains
  himself, having undertaken the training rules, seeing danger in the
  slightest fault. This is called the training in heightened virtue.</p>
</blockquote>

<p>My questions are :
1. What constitutes virtue ?(Any reference to Suttas would be great.If there are any books giving short summary of Patimokkha in English then that would also be great.)
2. How to train myself in virtue ? (Are there any training books available?)</p>
 254: <p>The <a href="https://en.wikipedia.org/wiki/Patimokkha" rel="nofollow noreferrer">Patimokkha</a> is one of the books of the Vinaya, i.e. the rules or code of conduct for monks.</p>

<p>There are English-language translations of (introductions to) the Vinaya <a href="https://www.accesstoinsight.org/tipitaka/vin/index.html" rel="nofollow noreferrer">here</a>, for example <a href="https://www.accesstoinsight.org/lib/authors/thanissaro/bmc1.pdf" rel="nofollow noreferrer">The Patimokkha Rules Translated &amp; Explained</a> by by Thanissaro Bhikkhu.</p>

<p>Dozens of suttas (e.g. SN 56.9) use the word <em>dhammavinaya</em>, translated as <a href="https://suttacentral.net/sn56.9/en/sujato" rel="nofollow noreferrer">teaching and training</a> and/or <a href="https://www.accesstoinsight.org/tipitaka/sn/sn56/sn56.009.wlsh.html" rel="nofollow noreferrer">Dhamma and discipline</a>.</p>

<p>You might like to read the original version of <a href="http://www.buddha-vacana.org/gloss.html#adhisilasikkha" rel="nofollow noreferrer">this dictionary entry</a> on the Buddhavacana web site -- it contains hyperlinks to to parts of the various suttas which it references:</p>

<blockquote>
  <p><a href="http://www.buddha-vacana.org/gloss.html#adhisilasikkha" rel="nofollow noreferrer">adhisīlasikkhā</a>: [adhi+sīla+sikkhā]</p>
  
  <p>training in higher virtue. A definition is given by the Buddha at AN 3.90. It consists of a thorough undertaking of the Pātimokkha's rules.</p>
  
  <ul>
  <li>Adhi·sīla·sikkhā is one of the three sikkhās, together with adhi·citta·sikkhā and adhi·paññā·sikkhā. It is said of these three trainings at AN 3.82 that they are 'ascetic tasks of an ascetic' (samaṇassa samaṇa·karaṇīyāni), at AN 3.93 that they are 'urgent tasks of a bhikkhu' (bhikkhussa accāyikāni karaṇīyāni), and at AN 6.30 that they constitute the 'supreme training' (anuttariyaṃ sikkhā) for the purification of beings, etc. (formula in the style of the Mahāsatipaṭṭhāna Sutta)</li>
  <li>They can even replace the Pātimokkha, in some cases (AN 3.85).</li>
  <li>However, adhi·sīla·sikkhā is not only for bhikkhus, since it should also be undertaken by upāsakas, as they meet with their success (sampadā) or their prosperity (sambhava), lest it is their their failure (vipatti) as in AN 7.30, their decline (parihāna) as in AN 7.29, or their ruin (parābhava) as in AN 7.31.</li>
  </ul>
</blockquote>

<p>AN 7.29 through AN 7.31 says that lay followers (<em>upāsakas</em>) too should practice "higher virtue", but don't define it.</p>

<p>I suspect that "higher" virtue means <em>more</em> than the five precepts.</p>

<p>Maybe in <a href="http://www.buddha-vacana.org/sutta/anguttara/03/an03-085.html" rel="nofollow noreferrer">AN 3.85</a> it's used instead of a detailed set of rules and definitions, and is used with "heightened discernment" (i.e. when you discern what's what, whether something is virtuous and skilful): in summary, "abandon the three poisons, don't do anything unskillful or engage in any evil".</p>
 471: <p>Virtue or sila at the very minimum is the <a href="https://www.accesstoinsight.org/ptf/dhamma/sila/pancasila.html" rel="nofollow noreferrer">five precepts</a>. Further practice of virtue is by the <a href="https://www.accesstoinsight.org/ptf/dhamma/sila/atthasila.html" rel="nofollow noreferrer">eight precepts</a>, <a href="https://www.accesstoinsight.org/ptf/dhamma/sila/dasasila.html" rel="nofollow noreferrer">ten precepts</a>, <a href="https://www.accesstoinsight.org/ptf/dhamma/sacca/sacca4/samma-ajivo/index.html" rel="nofollow noreferrer">Right Livelihood</a>, <a href="https://www.accesstoinsight.org/ptf/dhamma/sacca/sacca4/samma-vaca/index.html" rel="nofollow noreferrer">Right Speech</a> and <a href="https://www.accesstoinsight.org/ptf/dhamma/sacca/sacca4/samma-kammanto/index.html" rel="nofollow noreferrer">Right Action</a>.</p>

<p>Further information can be found in <a href="https://www.accesstoinsight.org/ptf/dhamma/sila/index.html" rel="nofollow noreferrer">AccessToInsight's virtue (sila) page</a>, including sutta verses.</p>

<p>To practice virtue (sila), the first step is to vow to undertake the training of the <a href="https://www.accesstoinsight.org/ptf/dhamma/sila/pancasila.html" rel="nofollow noreferrer">five precepts</a>, and then practice them with <a href="https://buddhism.stackexchange.com/q/22181/471">heedfulness (appamada)</a>.</p>

<p>The second step is to adopt this thinking from <a href="https://suttacentral.net/an5.57/en/bodhi" rel="nofollow noreferrer">AN 5.57</a>: </p>

<blockquote>
  <p>“And for the sake of what benefit should a woman or a man, a
  householder or one gone forth, often reflect thus: ‘I am the owner of
  my kamma, the heir of my kamma; I have kamma as my origin, kamma as my
  relative, kamma as my resort; I will be the heir of whatever kamma,
  good or bad, that I do’? People engage in misconduct by body, speech,
  and mind. <strong>But when one often reflects upon this theme, such misconduct
  is either completely abandoned or diminished</strong>. It is for the sake of
  this benefit that a woman or a man, a householder or one gone forth,
  should often reflect thus: ‘I am the owner of my kamma, the heir of my
  kamma; I have kamma as my origin, kamma as my relative, kamma as my
  resort; I will be the heir of whatever kamma, good or bad, that I do.’</p>
</blockquote>

<p>The third step is to understand more deeply from the Dhamma on <a href="https://www.accesstoinsight.org/ptf/dhamma/sacca/sacca4/samma-ajivo/index.html" rel="nofollow noreferrer">Right Livelihood</a>, <a href="https://www.accesstoinsight.org/ptf/dhamma/sacca/sacca4/samma-vaca/index.html" rel="nofollow noreferrer">Right Speech</a> and <a href="https://www.accesstoinsight.org/ptf/dhamma/sacca/sacca4/samma-kammanto/index.html" rel="nofollow noreferrer">Right Action</a>, and practise them with <a href="https://buddhism.stackexchange.com/q/22181/471">heedfulness (appamada)</a>.</p>
