(17) O mortal, when the House of Israel dwelt on their own soil, they defiled it with their ways and their deeds; their ways were in My sight like the uncleanness of a menstruating woman.
The Torah compares them to the impurity of a menstruating woman, whose husband is yearning for when she will be pure once again and be able to reunite (physically) with her.
(So, too, God, always yearns for the Jewish people to return from their evil ways and come back to him)
(19) I scattered them among the nations, and they were dispersed through the countries: I punished them in accordance with their ways and their deeds.
I scattered them among the nations: And from those nations I dispersed them among the lands. And despite this, it was not done in a way in which I was totally hiding from them, because I was still watching over them
(20) But when they came to those nations, they caused My holy name to be profaned, in that it was said of them, “These are the people of the LORD, yet they had to leave His land.”
But when they came: Since he refers to the "House of Israel" in the beginning of the chapter, he refers to them in the singular for the rest of it. And the Midrash says that it refers to God (singular) who traveled with them in exiled and bent his ear to listen to what they (the captors) were saying, which was "look, this is the nation of G-d," and he could not save them.
(22) Say to the House of Israel: Thus said the Lord GOD: Not for your sake will I act, O House of Israel, but for My holy name, which you have caused to be profaned among the nations to which you have come.
Not for your sake: Because if it was for your sake, it would depend on your merits and transgressions, and if you transgress more, you would be exiled for longer. But since I'm not doing all this for you but only for....
And what is the sanctification? the fact that I will take you out from among the nations in the next verse...
The verse that probably clinched that it would be the Haftarah for Parshat Parah,
(ה) רַבִּי לֵוִי בְּשֵׁם רַבִּי חָמָא בְּרַבִּי חֲנִינָא אָמַר חֻקִּים שֶׁהֵם חֲקוּקִים עַל יֵצֶר הָרָע, הֲדָא הוּא דִכְתִיב (ישעיה י, א): הוֹי הַחֹקְקִים חִקְקֵי אָוֶן, אָמַר רַבִּי לֵוִי מָשָׁל לִמְקוֹם אַדְרִימוֹן שֶׁהוּא מְשֻׁבָּשׁ בִּגְיָסוֹת, מֶה עָשָׂה הַמֶּלֶךְ הוֹשִׁיב בּוֹ קוֹסְטְרַיְנוֹס בִּשְׁבִיל לְשָׁמְרוֹ, כָּךְ אָמַר הַקָּדוֹשׁ בָּרוּךְ הוּא תּוֹרָה קְרוּיָה אֶבֶן וְיֵצֶר הָרָע קָרוּי אֶבֶן, תּוֹרָה קְרוּיָה אֶבֶן, שֶׁנֶּאֱמַר (שמות כד, יב): אֶת לֻחֹת הָאֶבֶן וְהַתּוֹרָה וְהַמִּצְוָה. יֵצֶר הָרָע קָרוּי אֶבֶן, דִּכְתִיב (יחזקאל לו, כו): וַהֲסִרֹתִי אֶת לֵב הָאֶבֶן מִבְּשַׂרְכֶם. תּוֹרָה אֶבֶן, יֵצֶר הָרָע אֶבֶן, הָאֶבֶן תִּשְׁמֹר אֶת הָאָבֶן.
(לג) כֹּ֤ה אָמַר֙ אדושם יי בְּיוֹם֙ טַהֲרִ֣י אֶתְכֶ֔ם מִכֹּ֖ל עֲוֺנֽוֹתֵיכֶ֑ם וְהֽוֹשַׁבְתִּי֙ אֶת־הֶ֣עָרִ֔ים וְנִבְנ֖וּ הֶחֳרָבֽוֹת׃
(33) Thus said the Lord GOD: When I have cleansed you of all your iniquities, I will people your settlements, and the ruined places shall be rebuilt;
Thus said the Lord GOD: When I have cleansed you: I am notifying you that after you repent entirely and purify your sins, where
(לז) כֹּ֤ה אָמַר֙ אדושם יי ע֗וֹד זֹ֛את אִדָּרֵ֥שׁ לְבֵֽית־יִשְׂרָאֵ֖ל לַעֲשׂ֣וֹת לָהֶ֑ם אַרְבֶּ֥ה אֹתָ֛ם כַּצֹּ֖אן אָדָֽם׃
