user-1: According to Buddhism, should one change oneself or change the world and why.

user471: The Buddha did not intend monks to participate in politics, as seen in DN 2:

"Whereas some brahmans and contemplatives, living off food given in
  faith, are addicted to talking about lowly topics such as these —
  talking about kings, robbers, ministers of state; armies, alarms, and
  battles; food and drink; clothing, furniture, garlands, and scents;
  relatives; vehicles; villages, towns, cities, the countryside; women
  and heroes; the gossip of the street and the well; tales of the dead;
  tales of diversity [philosophical discussions of the past and future],
  the creation of the world and of the sea, and talk of whether things
  exist or not — he abstains from talking about lowly topics such as
  these. This, too, is part of his virtue.

However, the Buddha did intend for lay people to participate in constructive nation building, in accordance with the Dhamma in DN 16:

At that time the Venerable Ananda was standing behind the Blessed One, fanning him, and the Blessed One addressed the Venerable
  Ananda thus: "What have you heard, Ananda: do the Vajjis have frequent
  gatherings, and are their meetings well attended?"
"I have heard, Lord, that this is so."
"So long, Ananda, as this is the case, the growth of the Vajjis is to
  be expected, not their decline.
"What have you heard, Ananda: do the Vajjis assemble and disperse
  peacefully and attend to their affairs in concord?"
"I have heard, Lord, that they do."
"So long, Ananda, as this is the case, the growth of the Vajjis is to
  be expected, not their decline.
"What have you heard, Ananda: do the Vajjis neither enact new decrees
  nor abolish existing ones, but proceed in accordance with their
  ancient constitutions?"
"I have heard, Lord, that they do."
"So long, Ananda, as this is the case, the growth of the Vajjis is to
  be expected, not their decline.
"What have you heard, Ananda: do the Vajjis show respect, honor,
  esteem, and veneration towards their elders and think it worthwhile to
  listen to them?"
"I have heard, Lord, that they do."
"So long, Ananda, as this is the case, the growth of the Vajjis is to
  be expected, not their decline.
"What have you heard, Ananda: do the Vajjis refrain from abducting
  women and maidens of good families and from detaining them?"
"I have heard, Lord, that they refrain from doing so."
"So long, Ananda, as this is the case, the growth of the Vajjis is to
  be expected, not their decline.
"What have you heard, Ananda: do the Vajjis show respect, honor,
  esteem, and veneration towards their shrines, both those within the
  city and those outside it, and do not deprive them of the due
  offerings as given and made to them formerly?"
"I have heard, Lord, that they do venerate their shrines, and that
  they do not deprive them of their offerings."
"So long, Ananda, as this is the case, the growth of the Vajjis is to
  be expected, not their decline.
"What have you heard, Ananda: do the Vajjis duly protect and guard the
  arahats, so that those who have not come to the realm yet might do so,
  and those who have already come might live there in peace?"
"I have heard, Lord, that they do."
"So long, Ananda, as this is the case, the growth of the Vajjis is to
  be expected, not their decline."


user13709: AN4.95 clearly lists the priorities of practicing to help oneself vs. others:
Not so good:

One who practices to benefit neither themselves nor others;

Better:

one who practices to benefit others, but not themselves;

Even better:

one who practices to benefit themselves, but not others; and

Best:

one who practices to benefit both themselves and others.

Notice that practicing to become a better person is seen as having more benefit that telling others how to practice. It sounds odd until you think about it, but when you think about it, would you follow the example of one who does not practice what they preach? 
Hence it is best to practice and help others practice, but it's also ok to just worry about your own practice until you can help others.

user700: Buddhism is not a religion that tries to change the world I think. Just like Buddhism don't give direct explanations of the nature of the universe. Buddhism's purpose is to lead people to experience the nature of reality themselves and give proper guidence to the people who have the intention to free themselves from suffering.
I remember a dhammaphada verse(thousands) that is not directly connected to this topic but I think it can give us some insight about Buddhism's approach to this subject

Greater in battle than the man who would conquer a thousand-thousand men, is he who would conquer just one — himself.
Better to conquer yourself than others. When you've trained yourself, living in constant self-control, neither a deva nor gandhabba, nor a Mara banded with Brahmas, could turn that triumph back into defeat.

If a person is interested to the core of Buddhism(meditation) most likely s/he  becomes less interested to changing the world, because meditation leads people to realize that trying to change or help others can be an ego demand and most of the things in the world are out of our influence. Also trying to change the world without changing oneself can cause harm to others because a person's state of mind directly influences the quality of his/her actions. But that doesn't mean that everyone who are deeply involved with meditation are less interested to changing the world. Trying to change the world can continue in the meditators as a habit even If the meditators greatly purify themselves. Meditation leads people to become more aware of the suffering of other living beings, so it is possible for a Buddhist meditator to become interested to change the world but eventually that desire would be diminished because of the realization of the uncontrollability of the forms and the degree of craziness of the humans.
Buddhism is not a political movement, don't have "Sharia Laws", don't try to conquer the world, forcibly trying to change an individual's desires or have rules that restricts people's freewill so it is up to the individual to decide to interfere the world politics or try to change the world or not. But "doing good deeds" to other people and living beings is certainly what Buddhism directly recommends to it's followers but that is not the same thing as trying to change the world I think.

-1: <p>According to Buddhism, should one change oneself or change the world and why.</p>
 471: <p>The Buddha did not intend monks to participate in politics, as seen in <a href="https://www.accesstoinsight.org/tipitaka/dn/dn.02.0.than.html" rel="nofollow noreferrer">DN 2</a>:</p>

<blockquote>
  <p>"Whereas some brahmans and contemplatives, living off food given in
  faith, are addicted to talking about lowly topics such as these —
  talking about kings, robbers, ministers of state; armies, alarms, and
  battles; food and drink; clothing, furniture, garlands, and scents;
  relatives; vehicles; villages, towns, cities, the countryside; women
  and heroes; the gossip of the street and the well; tales of the dead;
  tales of diversity [philosophical discussions of the past and future],
  the creation of the world and of the sea, and talk of whether things
  exist or not — he abstains from talking about lowly topics such as
  these. This, too, is part of his virtue.</p>
</blockquote>

<p>However, the Buddha did intend for lay people to participate in constructive nation building, in accordance with the Dhamma in <a href="https://www.accesstoinsight.org/tipitaka/dn/dn.16.1-6.vaji.html" rel="nofollow noreferrer">DN 16</a>:</p>

<blockquote>
  <p>At that time the Venerable Ananda was standing behind the Blessed One, fanning him, and the Blessed One addressed the Venerable
  Ananda thus: "What have you heard, Ananda: do the Vajjis have frequent
  gatherings, and are their meetings well attended?"</p>
  
  <p>"I have heard, Lord, that this is so."</p>
  
  <p>"So long, Ananda, as this is the case, the growth of the Vajjis is to
  be expected, not their decline.</p>
  
  <p>"What have you heard, Ananda: do the Vajjis assemble and disperse
  peacefully and attend to their affairs in concord?"</p>
  
  <p>"I have heard, Lord, that they do."</p>
  
  <p>"So long, Ananda, as this is the case, the growth of the Vajjis is to
  be expected, not their decline.</p>
  
  <p>"What have you heard, Ananda: do the Vajjis neither enact new decrees
  nor abolish existing ones, but proceed in accordance with their
  ancient constitutions?"</p>
  
  <p>"I have heard, Lord, that they do."</p>
  
  <p>"So long, Ananda, as this is the case, the growth of the Vajjis is to
  be expected, not their decline.</p>
  
  <p>"What have you heard, Ananda: do the Vajjis show respect, honor,
  esteem, and veneration towards their elders and think it worthwhile to
  listen to them?"</p>
  
  <p>"I have heard, Lord, that they do."</p>
  
  <p>"So long, Ananda, as this is the case, the growth of the Vajjis is to
  be expected, not their decline.</p>
  
  <p>"What have you heard, Ananda: do the Vajjis refrain from abducting
  women and maidens of good families and from detaining them?"</p>
  
  <p>"I have heard, Lord, that they refrain from doing so."</p>
  
  <p>"So long, Ananda, as this is the case, the growth of the Vajjis is to
  be expected, not their decline.</p>
  
  <p>"What have you heard, Ananda: do the Vajjis show respect, honor,
  esteem, and veneration towards their shrines, both those within the
  city and those outside it, and do not deprive them of the due
  offerings as given and made to them formerly?"</p>
  
  <p>"I have heard, Lord, that they do venerate their shrines, and that
  they do not deprive them of their offerings."</p>
  
  <p>"So long, Ananda, as this is the case, the growth of the Vajjis is to
  be expected, not their decline.</p>
  
  <p>"What have you heard, Ananda: do the Vajjis duly protect and guard the
  arahats, so that those who have not come to the realm yet might do so,
  and those who have already come might live there in peace?"</p>
  
  <p>"I have heard, Lord, that they do."</p>
  
  <p>"So long, Ananda, as this is the case, the growth of the Vajjis is to
  be expected, not their decline."</p>
</blockquote>
 13709: <p><a href="https://suttacentral.net/an4.95/en/sujato" rel="nofollow noreferrer">AN4.95</a> clearly lists the priorities of practicing to help oneself vs. others:</p>

<p>Not so good:</p>

<blockquote>
  <p>One who practices to benefit neither themselves nor others;</p>
</blockquote>

<p>Better:</p>

<blockquote>
  <p>one who practices to benefit others, but not themselves;</p>
</blockquote>

<p>Even better:</p>

<blockquote>
  <p>one who practices to benefit themselves, but not others; and</p>
</blockquote>

<p>Best:</p>

<blockquote>
  <p>one who practices to benefit both themselves and others.</p>
</blockquote>

<p>Notice that practicing to become a better person is seen as having more benefit that telling others how to practice. It sounds odd until you think about it, but when you think about it, would you follow the example of one who does not practice what they preach? </p>

<p>Hence it is best to practice and help others practice, but it's also ok to just worry about your own practice until you can help others.</p>
 700: <p>Buddhism is not a religion that tries to change the world I think. Just like Buddhism don't give direct explanations of the nature of the universe. Buddhism's purpose is to lead people to experience the nature of reality themselves and give proper guidence to the people who have the intention to free themselves from suffering.</p>
<p>I remember a dhammaphada verse(thousands) that is not directly connected to this topic but I think it can give us some insight about Buddhism's approach to this subject</p>
<blockquote>
<p>Greater in battle than the man who would conquer a thousand-thousand men, is he who would conquer just one — himself.</p>
<p>Better to conquer yourself than others. When you've trained yourself, living in constant self-control, neither a deva nor gandhabba, nor a Mara banded with Brahmas, could turn that triumph back into defeat.</p>
</blockquote>
<p>If a person is interested to the core of Buddhism(meditation) most likely s/he  becomes less interested to changing the world, because meditation leads people to realize that trying to change or help others can be an ego demand and most of the things in the world are out of our influence. Also trying to change the world without changing oneself can cause harm to others because a person's state of mind directly influences the quality of his/her actions. But that doesn't mean that everyone who are deeply involved with meditation are less interested to changing the world. Trying to change the world can continue in the meditators as a habit even If the meditators greatly purify themselves. Meditation leads people to become more aware of the suffering of other living beings, so it is possible for a Buddhist meditator to become interested to change the world but eventually that desire would be diminished because of the realization of the uncontrollability of the forms and the degree of craziness of the humans.</p>
<p>Buddhism is not a political movement, don't have &quot;Sharia Laws&quot;, don't try to conquer the world, forcibly trying to change an individual's desires or have rules that restricts people's freewill so it is up to the individual to decide to interfere the world politics or try to change the world or not. But &quot;doing good deeds&quot; to other people and living beings is certainly what Buddhism directly recommends to it's followers but that is not the same thing as trying to change the world I think.</p>
