What to do when nations are at war-

Speaking in November of 1983, the Rebbe began by explaining the unique power a Jew has to affect the world around him: 

 Everything in the world revolves around and is dependent upon Jews and their conduct. A Jew’s service to G‑d has tremendous repercussions, and therefore the appropriate response to the increasing trouble in the world is to increase service to G‑d. As long as G‑d is in exile among the nations — they do not recognize His sovereignty — they do not act consonant to His will. When Jews, through an increase in their service, redeem G‑d from exile, the nations will automatically behave properly. 

So how do we save the world? 

 The Rebbe made it as simple and practical as could be imagined: 

  Look at the Jewish world. Is there peace among Jews? Are there situations where Jews, too, are provoking one another? Repair that, and you will repair the world. 

You don’t have to resolve every conflict between human beings. When you bring a little more love and harmony just between the Jews you know, you will bring enlightenment and peace to the nations. But the Rebbe got far more practical: Make this part of your daily morning routine, he said. Before you start your prayers in the morning, make a commitment to show only love to every fellow Jew. And after completing your prayers, make another commitment to support the stability and harmony of the world around you. You may think that’s a small thing. The Rebbe is telling you that you are bringing powerful nations to lay down their arms. Practically speaking: Whatever your prayer routine, whatever prayer book you use, whatever your background or beliefs—take the Rebbe’s advice and say these words before and after your prayers. Ponder them. Follow through on them. As the Rebbe put it, with just a little love and kindness we can bypass any further suffering and welcome in the times of Moshiach right now. 

 1. Start each morning by saying, “I commit myself to fulfill the mitzvah of loving my fellow like myself.” הֲרֵינִי מְקַבֵּל עָלַי מִצְוַת עֲשֵׂה שֶׁל וְאָהַבְתָּ לְרֵעֲךָ כָּמוךָ: 

 2. After your morning prayers, make sure to say, “Indeed, good people will praise Your name. Upright people will sit in Your presence.” 

אַ֣ךְ צַ֭דִּיקִים יוֹד֣וּ לִשְׁמֶ֑ךָ יֵשְׁב֥וּ יְ֝שָׁרִ֗ים אֶת־פָּנֶֽיךָ׃ 3. Follow Hillel’s golden rule: “If you wouldn’t like it done to you, don't do it to the other guy.” 

 4. Speak only good about fellow Jews. Don’t even listen to a bad word, unless some real benefit will come through your conversation. 

 5. Care for the other guy’s property and possessions as you care for your own. 

 6. Always be on the lookout for opportunities to do a favor, especially for a fellow Jew 

 7. Bring people together, especially Jewish people. Tear down the false barriers of age, affiliation and ethnicity. 

 8. Invite other Jews to share in the most precious thing we have, our Torah and mitzvahs. 

 Taken from essay written by Rabbi Tzvi Freeman; Chabad.org