וְקִבַּצְתִּי֙ אֶת־כָּל־הַגּוֹיִ֔ם וְה֣וֹרַדְתִּ֔ים אֶל־עֵ֖מֶק יְהֽוֹשָׁפָ֑ט וְנִשְׁפַּטְתִּ֨י עִמָּ֜ם שָׁ֗ם עַל־עַמִּ֨י וְנַחֲלָתִ֤י יִשְׂרָאֵל֙ אֲשֶׁ֣ר פִּזְּר֣וּ בַגּוֹיִ֔ם וְאֶת־אַרְצִ֖י חִלֵּֽקוּ׃
װעל איך אײַנזאַמלען אַלע פֿעלקער, און איך װעל זײ מאַכן נידערן אין טאָל פֿון יהוֹשָפָֿט, און איך װעל זיך דאָרטן משפּטן מיט זײפֿאַר מײַן פֿאָלק און מײַן אַרב ישׂראל, װאָס זײ האָבן זײ צעשפּרײט צװישן די פֿעלקער, און צעטײלט מײַן לאַנד.
Abarbanel
1. "Thus said Hashem for the three sins of Damascus..." Amos the prophet was prophecising here about six non Jewish nations. Damascus was the head of the kingdom of Aram, Aza the head of the Phillistine kingdom, Tzur, Edom, Amon and Moab. Why aren't the other nations who also attacked and destroyed Israel mentioned here (eg Babylon, Egypt...). I see two possible reasons. The first is that Amos connected his prophecy to that of Yoel. Yoel's prophecy mentioned the two destructions of the Temple and their judgement ("I will gather the nations and bring them to the valley of judgement and there I will judge them regarding my lot, Israel, that they scattered among the nations and my people they divided" Yoel 4:2) and there it specifically mentions Egypt and Edom becoming a waste. Egypt there refers to the lands of the Ishmaelites who joined the Babylonians in destroying the first temple. Edom refers to Rome who destroyed the second temple. Amos therefore doesn't need to include these nations (Rome? Egypt? Babylon?) in his prophecy about the other nations. He includes nations that Yoel didn't speak of. Yosel does mention Tzur and Sidon and Amos also speaks of Tzur because Tzur was destroyed two times likes it says in Isiah. The first was through Nevudnezer who conquered Tzur and made a great slaughted there. The second conquering of Tzur was through Alexander (the Great?) who destroyed Tzur's army and walls and throughoughly destroyed it that no inhabitants were left there until this day. And Yoel spoke of the final great destruction of Tzur, whereas Amos's prophecy about Tzur referred to the first destruction that would take place through Nevuchadnezer. Also regarding Edom, Yoel said it would become a "desolate wilderness" and Amos also mentioned Edom in his prophecy. Yoel was referring to the Roman Empire and Amos was discusing the sins of Edom connected to Jerusaem and the burning of the south. This is the first reason why the prophet Amos doesn't bring up the other nations who attacked Israel. And the second reason is that the prophet is bring a proof and a reproof for Israel from their wicked neighbors. That if Gd punishes the nations who don't have a connection to Him and don't have the Torah for their sins, how could He also not punish His nation, Israel. And because they accepted the Torah they were more stricken by punishment than the other nations and therefore Amos only brought up examples of close by neighbors to Israel who were punished and not far out island nations (for example Rome). And now I will explain how the punishments are connected to these nations and to Judah together when Israel found themselves in a more serious judgement than the nations and therefore the other sins aren't mentioned only the sins that nations did that are connected to israel.
Or HaChaim
ועתה הנה הבאתי, "And now, here I have brought, etc." We have mentioned repeatedly that whenever the Torah uses the word עתה it has a connotation of תשובה, repentance. The person whom the Torah describes as reciting this prayer is a penitent. Although we have described him as having already been a resident in the terrestrial Gan Eden which certainly places him amongst the select group of the righteous, this is not enough when one desires entry to the celestial Gan Eden. Here we deal with the mystical dimension of the judgment G'd subjects the souls to in the future, something referred to as עמק יהושפט, [compare Yoel 4,2 where this location is described as where G'd judges the survivors of the war of Gog and Magog Ed.]. Even the prophet Samuel dreaded to face this final judgment and this is why he was so upset when the necromancer brought him back at the behest of King Saul (compare Midrash Tehillim 8 and Chagigah 4). This Midrash claims that there never was nor ever will be a valley named "the valley of Yehoshophat," i.e. that the name Yehoshaphat is a combination of the Hebrew for "G'd will judge."
Rashi
I have seen how the wicked were buried. In this prophecy, I saw wicked men buried, who were worthy of being buried in the dust, for they were held in contempt by the nations, about whom it is stated, “this people has never been,”19Yeshayahu 23:13. and they ruled over the Beis [Hamikdosh] of the Holy One, Blessed Is He, which is a holy place. And when they went from there to their land, they boasted in their city that they did such and such in the Beis [Hamikdosh] of the Omnipresent. Do not read ‘וְיִשְׁתַּכְּחוּ’, [=and they will be forgotten,] but ‘וְיִשְׁתַּבְּחוּ’, [=and they will boast]. So did our Rabbis of blessed memory expound it.20See Maseches Gittin 56b. Concerning the forgetting,21I.e., the wording of the written text [וישתכחו]. it is expounded as follows in the Aggadah: And ultimately, their name and their remembrance will be forgotten from that very city, that they did so therein, as it is stated, “I will gather all the nations [and I will take them down] to the Valley of Yehoshophot.”22Yoel 4:2. In the place where they angered Him, He will mete out retribution upon them, and so it states, “O Adonoy, in the city, You will despise their form.”23Tehillim 73:20.