The haftorahs for the first day and Shabbos of Sukkos depicts the war of Gog and Magog and its aftermath. There will be great chaos and bloodshed but, in the end, there will be open miracles which will result in the whole world recognizing Hashem as one. (It is worthwhile to read both haftorahs with commentaries inside.)
The pasuk in the haftorah for the first day of Sukkos, which we actually say every day at the end of Pesukei Dizimra, and repeat many times in our Yomim Noraim davening, says “Then Hashem will be king over all the world, on that day Hashem will be One and his name will be One” (Zechariah 14:9). Rashi on this pasuk says that every non-Jew will leave their gods and there won’t be any nation worshiping a foreign god, and Hashem’s name will be known and mentioned by everyone. Later in the haftorah the prophet Zechariah relates, “It shall be that all who are left over from all the nations who had invaded Yerushalayim will come up every year to worship the King Hashem, Master Of Legions, and to celebrate the festival of Sukkos” (Zechariah 14:16). The Radak there says the reason why the whole world will come together in Yerushalayim on Sukkos is because at that time of the year will be the war and when they will see all the wonders of the Blessed Creator. Therefore, to commemorate that event, they will come each year at this time.
Rashi cryptically says this pasuk is what Chazal explain in gemara Avoda Zara daf 3a-3b about an easy mitzvah Hashem will give the non-Jews to do which will be sukkah.
Here is the beginning and the ending of Hashem’s conversation with all the non-Jewish nations (taken from Soncino translation): Daf 2a: R. Hanina b. Papa — some say R. Simlai — expounded [the foregoing verse] thus: In times to come, the Holy One, Blessed Be He, will take a scroll of the Law in His embrace and proclaim: ‘Let him who has occupied himself herewith, come and take his reward.’ Thereupon all the nations will crowd together in confusion, as it is said: All the nations are gathered together, etc.
Daf 3a-3b: The nations will then plead. ‘Offer us the Torah anew and we shall obey it.’ But the Holy One, blessed be He, will say to them, ‘You foolish ones among peoples, he who took trouble [to prepare] on the eve of the Sabbath can eat on the Sabbath, but he who has not troubled on the eve of the Sabbath, what shall he eat on the Sabbath? Nevertheless, I have an easy command which is called Sukkah; go and carry it out.’ (But how can you say so: does not R. Joshua b. Levi say: What is [the meaning of] the verse, the ordinances which I command thee this day to do them? It is that this day only [the present] is the time to do them,’ they cannot be done tomorrow [in times to come]: this day is the time in which to do them, but not in which to be rewarded for them. [Why then should they be offered this observance in the Messianic time?] — Because the Holy One, blessed be He, does not deal imperiously with His creatures. And why does He term it an easy command? — Because it does not affect one’s purse.) Straightaway will every one of them betake himself and go and make a booth on the top of his roof; but the Holy One, blessed be He, will cause the sun to blaze forth over them as at the Summer Solstice. and every one of them will trample down his booth and go away, as it is said, Let us break their bands asunder, and cast away their cords from us. (But you have just said ‘The Holy One, blessed be He, does not deal imperiously with his creatures? — True! but with the Israelites, too, it occasionally happens that the summer solstice extends till the Festival [of Tabernacles] and they are vexed [by the heat]. But does not Raba say: He who is vexed thereby is freed from dwelling in the Sukkah? — Granted, they would [in such circumstances] be freed, but would Israelites contemptuously trample it down?)
With Rashi’s direction we can put the gemara of Avoda Zara into perspective. In the aftermath of the war of Gog and Magog everyone, Jew and non-Jew, will recognize Hashem as one and His will to follow; no turning back, this will be it. A new chapter in history, a new world order, which everyone will embrace. Hashem is going to gather everyone together to collect their earned reward, and in His ever-abundant mercy will even give the non-Jewish nations another chance, an easy chance to earn their pay; but they will squander the opportunity by belittling the mitzvah given to them. But putting the situation into perspective something doesn’t make sense! Coming together on sukkos they will be commemorating their Independence Day, liberation from the chaotic world they once lived in. They will now have a complete clarity and devotion to Hashem. So how can they belittle the mitzvah Hashem gave them by kicking the sukkah, even if they got frustrated that they couldn’t fulfill the mitzvah because it was too hot? Where will their faith and trust in Hashem be?
Furthermore, the Haftorah continues, Pasuk 17: “And it shall be that whoever of all the families of the earth does not go up to Jerusalem to prostrate himself to the King, the Lord of Hosts-upon them there shall be no rain.”
Rashi there comments, “rain: Actual rain to cause the produce of their land to grow. Now, what reason did He have for decreeing upon them the withholding of rain? That the commandments of the festival are based on the rains: the four species of the lulav and the water libation are to appease God for water. Since the festival of Tabernacles is the time of the rains of the year, no rain will fall on those who entertain doubts concerning the festival of Tabernacles. This is learned in the Tosefta of Sukkah (4:7).”
Pasuk 18 states: And if the family of Egypt does not go up and does not come, it shall not [rain] upon them. The plague [on Egypt] will be [the same as] that with which the Lord will plague the nations who do not go up to celebrate the festival of Tabernacles.
How can any of the family of nations think not to come up to Yerushayim for sukkos, their Independence Day, if they have complete belief in Hashem, His Will, and reward and punishment?
It would seem though, that when the gemara in Avoda Zara says the reason why the non-Jews don’t deserve reward is because only those that toil on the eve of shabbos get there reward on shabbos, meaning only if one works hard in performing Torah and mitzvos in this world does he receive his well-earned reward in the next world, it not only is a message about the reward received but a message about how the reward is earned. Meaning, because the Jewish people as a whole not only performed but worked hard and struggled to perform Torah and mitzvos throughout history they rightfully deserve that reward but they also appreciate more what it means to perform a mitzvah and do Hashem’s Will. So they would never get upset and belittle a mitzvah just because they lost their chance and became exempt from the mitzvah. On the contrary many people would just feel disappointed on losing the opportunity to fulfill the mitzvah. But this is because we spent many years observing and appreciating what a mitzvah is all about. The rest of the nations of the world will realize the true path one day, but won’t have the experience and work ethic to appreciate what they are given by Hashem. Therefore, even when the whole world unifies to believe in the one and only G-D and to fulfill his will, it will still be hard for them in the beginning even if they will never stop believing, just because they haven’t worked hard yet at performing and walking in the way of Hashem.
This appreciation derived from a proper work ethic in learning Torah and performing mitzvos is something that can apply to us even today. It might be difficult for converts or even baalei Teshuva who come back to their faith and want to keep the mitzvos and learn tons of Torah. In fact potentially any Jew has his or her ups and downs, but it’s still hard and frustrating. This could be due to the fact that most aren’t used to it, but with a commitment to never give up and to keep on trying, to build up the work ethic needed to perform Torah and mitzvos properly, then a person will appreciate the path of walking in the ways of Hashem, whichever direction it leads. In this way he will rightfully earn his due reward.