Jeremiah 12:15 - Ellicott's Commentary On The Whole Bible

I will return, and have compassion on them. — The words refer, as Jeremiah 12:16 shows, not to Judah only, but to the “evil neighbours.” For them also there is hope, and that hope is bound up with the return of Judah. Strong as was the prophet’s desire for retribution, it is overpowered by the new love shed abroad in his soul, and he sees that it does not exclude, even in their case, the pity and the yearning that look beyond it for an ultimate restoration.