This reading, like most Haftarot, echoes the Torah portion. In the Torah reading, we learn about Nadav and Avihu bringing an "unorthodox" sacrifice, and the steps which Aaron and Moses had to take to repair the spiritual damage. Finally, the Israelites are taught the rules of kashrut, in a parallel practice to the "kosher" and "non-kosher" sacrifices. The Haftorah follows a similar theme on a national scale. When the people have strayed, they are exiled from the Land of Israel. However, in order to avoid this "reflecting badly" on G*d, He redeems them -- emphasizing that this is done not for their merit, but His glory -- and restores them to the land. Now they are instructed to follow the commandments in order to merit this redemption:
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. 23 I will sanctify My great name which has been profaned among the nations — among whom you have caused it to be profaned. And the nations shall know that I am the Lord — declares the Lord God — when I manifest My holiness before their eyes through you. 24 I will take you from among the nations and gather you from all the countries, and I will bring you back to your own land. 25 I will sprinkle clean water upon you, and you shall be clean: I will cleanse you from all your uncleanness and from all your fetishes. 26 And I will give you a new heart and put a new spirit into you: I will remove the heart of stone from your body and give you a heart of flesh; 27 and I will put My spirit into you. Thus I will cause you to follow My laws and faithfully to observe My rules. 28Then you shall dwell in the land which I gave to your fathers, and you shall be My people and I will be your God.We see here the progression of the relationship between G*d and His people. At first, He is angry with us for straying. In His anger, He seems concerned only for how we are making Him look bad... So He reaches out unilaterally to redeem us, to bring us back to our land, and to set us back on the right path. In so doing, the relationship is restored: "you shall be My people and I will be your God" -- "I am my beloved's and my beloved is mine".
I recently came across this article by a Christian rejecting the "love the sinner but hate the sin" meme, not just as it is often used in connection with homosexuality, but in general. Christians often see G*d's freely offered redemption through Jesus's sacrifice as a contrast to a vengeful Old Testament G*d. But here we see that the notion of G*d extending "grace" is alive and well in the Old Testament, albeit couched in the notion of "I'm doing this for MY OWN GLORY, not because y'all are so deserving, cuz yer not!" Interestingly, this may be a more realistic model for us imperfect (and often vengeful) humans to follow. In our relationships, can we in fact "put a new spirit" into our relationships, without waiting for others to "fix" themselves? Not because they have "earned" it, but because it is the right thing to do? If nothing else, because doing so would make us look better than being petty?