Joel 3:17 - Coke's Commentary on the Holy Bible

Then shall Jerusalem be holy— That is, "After this, Jerusalem shall be safe under my care, and be no more profaned by the hostile armies of these mine enemies." These expressions, perhaps, may have a further reference; and as we have found in the former prophets, that, under predictions of deliverances from particular enemies, great and future deliverances also in some remote ages are signified, this possibly may be the case with this latter part of Joel's prophesy; wherein it has been thought by some (and I doubt not is the case), that he refers to the great and final restoration of the Jews, when the fulness of the Gentiles shall be come in.