John Gill Commentary Jeremiah 30:14

"All thy lovers have forgotten thee; they seek thee not: for I have wounded thee with the wound of an enemy, with the chastisement of a cruel one, for the greatness of thine iniquity, because thy sins were increased." — Jeremiah 30:14 (ASV)

All your lovers have forgotten thee
The Egyptians and Assyrians, whom they sought unto for help, and entered into an alliance with, and who promised them great things; but forgot their promises and forsook them:

they seek thee not ;
to ask of your welfare, as the Targum adds; they do not, visit thee, nor inquire after your health, or how it is with thee, having no manner of care and concern for thee; this has been the case of the Jews for many ages:

for I have wounded thee with the wound of an enemy, with the
chastisement of a cruel one ;
so it might seem to be; and thus it might be interpreted by them, as if the Lord acted the part of an enemy, and a very cruel one, that had no mercy; though he corrected them, as in (Jeremiah 30:11) , in measure, moderation, and mercy: or else the meaning is, that he wounded them, when their nation, city, and temple, were destroyed, by the hand and means of an enemy, even a very cruel and merciless one, the Romans:

for the multitude of your iniquity; [because] your sins were increased ;
a very wicked people the Jews were, not only before they went into the Babylonish captivity, but after their return; and in the times of Christ and his apostles; who complain of their covetousness, hypocrisy, adultery, thefts, murders, and sacrilege; and particularly they were in the above manner chastised by means of the Romans, for their unbelief and rejection of the true Messiah, and the persecution of his followers.