Midrasch zu Amos 1:9

“They heard that I sigh; there is no comforter for me; all my enemies heard of my misfortune, were glad because You acted. May You bring the day that You proclaimed, and they will be like me” (Lamentations 1:21).
“They heard that I sigh.” Rabbi Yehoshua interpreted the verse regarding Aaron. You find that when Aaron died, the clouds of glory were dispersed and all Israel gathered to eulogize him. They said: ‘Moses is mourning, Elazar is mourning; who will not mourn?’ Immediately, what is written there? “The Canaanite king of Arad…heard” (Numbers 21:1). And it is written: “He waged war with Israel and he took captive from them” (Numbers 21:1).
The Rabbis interpret the verse regarding the destruction of the Temple. You find that wherever Israel sought to flee, [the local population] would turn them in. They sought to flee northward, but they did not allow them to do so. That is what is written: “For three transgressions of Gaza, but for the fourth, I will not relent: For their exiling of an entire exile, to deliver to Edom” (Amos 1:6). They sought to flee eastward, but they did not allow them to do so. That is what is written: “For three transgressions of Tyre, but for the fourth, I will not relent: For their delivering of an entire exile to Edom, and they did not remember the covenant of brothers” (Amos 1:9). They sought to flee westward, but they did not allow them to do so, as it is written: “A prophecy of Arabia: In the forest in Arabia you will stay the night, caravans [of Dedanites]” (Isaiah 21:13).²¹²The implication is that the fleeing exiles were stuck in the forest. The following verses describe how the local population should have greeted them with bread and water, but failed to do so.
“Because You acted,” this is analogous to a king who married a noblewoman. He said to her: ‘Do not speak to your friends. Do not borrow from them and do not lend to them.’ Sometime later the king grew angry at her and expelled her from the palace. She circulated among all her neighbors, but they did not receive her, so she returned to the palace. The king said to her: ‘You have been impudent!’²¹³It was impudent of you to return to the palace. The noblewoman said to the king: ‘My lord, had I lent them or borrowed from them a vessel, and I would have grown friendly with them, would they not have received me?’ So too, the Holy One blessed be He said to Israel: ‘You have been impudent!’ They said before Him: ‘Master of the universe, did you not write in Your Torah: “You shall not marry them; your daughter you shall not give to his son, and his daughter you shall not take for your son” (Deuteronomy 7:3)? Had we lent them and taken from them and them from us, and his daughter would be with me or my daughter with him, would they not have received me?’ That is: “Because You acted.”²¹⁴We are in this predicament because of what You did in issuing these commands. “May You bring the day that You proclaimed, and they will be like me,” in distress, and not like me in relief.²¹⁵Israel’s distress will ultimately end with redemption.

(Devarim, Ibid.) "lest their oppressors estrange them": When Israel is in distress, the nations estrange them, as if they did not exist in the world. And thus we find that when Israel wanted to flee to the north they handed them over (to their foes), viz. (Amos 1:9) "Thus said the L-rd: For three transgressions of Tyre, etc." When they wanted to flee to the south, they handed them over, viz. (Ibid. 6) "Thus said the L-rd: For three transgressions of Azza, etc." When they wanted to flee to the east, they handed them over, viz. "Thus said the L-rd: For the three transgressions of Damascus, etc." When they wanted to flee to the west, they handed them over, viz. (Isaiah 21:13) "The prophecy for Arav: In the forest, in Arav shall you lodge, O caravans of the Dedanites, etc."